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Introduction JD Welch Anna Reponen PE 483 – Final Project 3/14/2009 An analysis is a “separation of a whole into its component parts,” according to the Merrian‐Webster dictionary. So the analysis of a sprint start is the separation of all the components that make it up. This can be viewed as the separation of the sprint start into different phases. If one separates a sprint start into different phases, it can also be further analyzed through the use of different methods. The different methods are timing of the different phases; anatomical breakdowns, which are done by determining which muscles are being used in the phases; the determination of joint angles and body positions during those phases. The sprint start has always made an athlete a competitor in a race. Starting off of the blocks in a lighting fast manner allows for least time lost and optimal acceleration. The different phases of the sprint start are the “On Your Mark”, “Set”, “Go,” and “First Step/Front Leg Extension”. In the “On Your Mark” phase, the major joint contributions are primarily those of the shoulders, due to having to hold the pressure from the legs against the hands. “Set” phase uses the hips, knees and shoulders. The hips and knees press the pelvis upwards while the hands and arms support the upper body. The major joints being used in the “Go” phase are the rear knee and ankle as well as the extension of the rear hip. The final phase, “First Step/Front Leg Extension,” utilizes the ankle, knee and hip of the front leg and the lower back is used to pull the body upwards. The shoulders and arms are now only supporting the arms weight as well as all inertia created by the motion. All videos were watched and analyzed through http://www.YouTube.com. Breaking down a sprint start is easier done with the understanding of what is essential for an efficient start. Literature on sprint starts helped determine what phases were used for the rest of the project. The information read came from Gerry Carr’s second edition of Sport Mechanics for Coaches. In this book, Carr describes the forces that are going on in a sprint start. He says that in a sprinting start block situation, the sprinter puts a muscular force against the blocks in order to create an action. Following that action, the reaction is the push back that comes from the earth in an equal and opposite force against the athlete. The force created by a sprinter allows the sprinter to move forward by overcoming the inertia of their body mass. A sprinter’s body mass is directly related to how much muscle force that they can create; thus, the less massive the sprinter, the faster they will accelerate. Also, the more force a sprinter applies the faster their acceleration will be. This is an example of Newton’s Law of Acceleration: force = mass x acceleration. Carr gives a wonderful example to illustrate the relationship between a sprinter and the earth. He describes the movement by compressing a spring between a heavy shot put ball and a tennis ball. The shot put is the earth, the spring is the sprinter’s muscles and the tennis ball is the sprinter. When you let go of both balls, the tennis ball shoots out and the shot put stays relatively stationary. This explains why the sprinter shoots out in one direction and the earth moves in an immeasurable amount in the opposite direction. The book Applied Kinesiology, by Jensen, Clayne R., and Gordon W. Schultz, has a section in it that covers the topic of overcoming inertia from stationary positions in sprint blocks. It describes the body as being in an inclined position in the anticipated direction of the movement so that the center of gravity may be quickly shifted off balance in that direction. As the sprinter comes out of the blocks in a start they use short and powerful strides in order to accelerate rapidly. Some of the reasons for the short strides are that their base must be re‐established because of the extreme forward body lean to begin with and also so that the leg joints can experience their optimum mechanical advantage through just a small range of motion. Hip rotation is limited because hips should be flexed during acceleration and as the sprinter comes to the erect running position the hips should be less flexed, thus allowing the sprinter to have longer running strides. A sprinter’s arms are also important to their acceleration because the momentum of the arm movement is transferred to the body to help with acceleration through hard driving actions of the arms. The correct arm action should be more forward and less diagonal during the acceleration of a sprint start. Also Jensen, Clayne R., and Gordon W. Schultz note that adequate friction between the running surface and the sprinter’s feet is essential for fast starts. After understanding what is needed to ensure an efficient sprint start, the next step is to create new techniques and exercises to increase the speed in which the sprinter can achieve. Introduction of new practice strategies are a part of every sport. It is essential to understand the reasoning for the new practice strategies that have been created. One of these new strategies is to use weights while doing sprints. The use of weights while doing moderate activities has been essential in the conditioning of the body with the general understanding that the body will adapt to the change and become strong enough to carry the weight. The use of weights has been overlooked in sprinting due to the decrease in velocity for the individual. The researchers chose 24 participants that were enrolled in the physical education program at the university in which the study was being performed. The participants were all male and averaged the age of 20. Participants were performing regular physical activities such as running and lifting weights, along with extracurricular sporting activities that were considered games, combat or middle distance running. (R, R., M, K., D, U., D, M., & S, J. 1998) A recent study performed measured the amount of velocity in sprinting by either loading the arms or legs. The participants had to hold “…0, 1, 2, or 3 short lead rods…” in their hands or had “…load belts of 0, 0.6, 1.2, or 1.8 kg [that] were fastened above the ankle joint of each leg.” (R, R., M, K., D, U., D, M., & S, J. 1998) The subjects were asked to use their weight for a 4 week period to allow for their body to adapt to the change, and they were asked to put “…emphasis on all‐out acceleration and maintenance of the maximal running velocity.” (R, R., M, K., D, U., D, M., & S, J. 1998) The results of this study showed that the higher the amount of weight applied to the legs, the slower the velocity. The stride length did not change; however, the rate of stepping did change. With the application of weight to the arms there was no change in rate of stepping or stride length but there was a decrease in velocity. When training for an event or sport, there are always optimal strategies that can be performed. The one thing that seems to have trainers at ends is the question of what resistance training should be done to increase explosiveness off the block: some type of training regiment that will increase the “acceleration phase,” specifically the acceleration phase of a sprint start. Lifting weights will build the muscle and increase its size, and thus lifting weights decreases the speed in which the action can be performed. So is the trick to create an exercise that does not increase the size of the muscle in order to allow for retention in speed? Or is it that lifting takes place at such a slow rate that the muscles then become slow? At the University of New Brunswick in Canada, researchers concocted a plan to establish what lifts will encourage an increase in the “acceleration phase” of sprinting. The first things that the researchers established was which lifts are most like the action being performed. In this case, lifting ended up being “…a traditional and split technique, at a range of external loads from 30–70% of one repetition maximum” (Sleivert, Taingahue, 2004). However, the participants were not lifting as much weight as possible when squatting. The specific type of squats performed were “…concentric jump squats” (Sleivert, Taingahue, 2004) . The researchers who performed this study came to the conclusion that both squat types encouraged an increase in 5 m sprint times. The utilization of jump squats focused on explosiveness with weight resistance compared to body weight. The jumping action relates to the start off the blocks in which the body is being accelerated away from feet placement. This means that lifting in a manner in which there is resistance down, that is, greater than regular body weight, the body will compensate and adapt to the challenge and increase the rate in which the body accelerates. The journal article, Effects of arm and leg loading on sprint performance, investigated the effects of muscle‐tendon length on the joint movement and power during maximal sprint starts. For their methods, the researchers had nine male sprinters perform their maximal sprint starts from blocks that were adjusted to either forty degrees or to sixty‐five degrees horizontally. They recorded the ground reaction forces and the kinematics of the sprinters with a camera. Then they analyzed the joint movements and forces. The muscle‐tendons they analyzed were the gastrocnemius, soleus, vastus medialis, rectus femoris, and the biceps femoris. Their results showed that the block velocity was greater in the forty degree than in the sixty‐five degree block angle. They also noted that the initial lengths of the gastrocnemius and soleus of the front leg and the rear leg at the beginning of the force phase to the middle of the phase was longer in the forty degree than in the sixty‐five degree block. However, the initial lengths of the rectus femoris and the vastus medialis of the front leg were longer in the sixty‐five degree than in the forty degree block. Also, the peak ankle joint and power for the front and rear legs were greater in the forty degree block and the peak knee joint moment of the rear leg was greater in the sixty‐five degree block. Based upon their results, they found that the longer the initial muscle‐tendon lengths of the gastrocnemius and the soleus in the starting blocks at the beginning of the force production can create a greater peak ankle joint causing a greater velocity during a sprint start. The website Running Online: Your Online Running Partner described a few sprint starting drills that can be done to help an athlete perform the correct form during their sprint start. They placed the emphasis on the start because the start is what allows the sprinter to achieve their best sprinting form the quickest. The first drill is a low standing start where the sprinter stands with their feet about one and a half to two foot lengths from the starting line, bend over at the waist and letting their arms dangle downward toward the starting line. Then they slowly shift their weight forward until they begin to lose balance. The second drill is called a four‐point start. They do the same routine as they did in the low standing start except both hands, on their fingertips, are placed on the track behind the starting line. The third drill is the block placement drill, where the blocks are placed so the front block is one and a half to two foot lengths from the starting line and place the rear block so it is two and a half to three foot lengths from the starting line, and then the sprinters practice coming off of the blocks. The last drill is the “on your marks” command. The sprinter places their feet against the blocks as they crouch into them. Their hands are approximately shoulder width apart and behind the starting line and their weight is evenly distributed between their hands, the foot of the front leg, and the knee of the rear leg. Also, the sprinter’s head is relaxed while their whole body is being kept in balance as they practice this stance with the appropriate starting commands. These drills should help a sprinter become more efficient at performing their sprint starts out of the blocks. After determining what types of exercise and training techniques needs to be implemented, the trainers need to now look at how the body is affected at a cellular level. The article Physiological demands of running during long distance runs and triathlons had a research goal to identify the metabolic factors that influence the energy cost of running during prolonged exercise runs and triathlons. Hausswirth and Lehenaff proposed that there is a physiological comparison of running and triathlons and the relationship between running economy and performance. The term running economy can be synonymous with oxygen cost, metabolic cost, energy cost of running, or oxygen consumption. Marathons and triathlons modify biological constraints of athletes and have an influence on their running efficiency. The factors that may influence the energy cost of running are environmental conditions, participant specificity, and metabolic modifications. They Hausswirth and Lehenaff found that the various energy cost of prolonged running may only be explained by combined physiological and biomechanical processes. For exercises lasting more than two hours, the running economy is more pronounced at the end of a long run when compared to a triathlon lasting the same time, due to the elevated levels of free fatty acids and circulating glycerol. They (who’s they?) suggest that further studies should be done to understand the mechanisms behind endurance efforts. In the 100 m sprint, there are 8 individuals competing against each other to see who comes out on top. One issue that has come up in the past is lane placement, and if this has any impact on how fast one might be. Now the question of, why would lane placement matter? It matters because the runners on the inside of the track, the ones closest to the starting pistol, hear the “Go” shot earlier than the participants in the furthest lane. The “Go” shot dB level or loudness was also greatest with the participants that were closest to the starting pistol. This research article, Go Signal Intensity Influences the Sprint Start, looked at the reaction times of the 2004 Olympic Games to see if the participants’ reaction times correlated with the hypothesis of the researchers. What they found was that the participants that were closest to the starting pistol had significantly lower reaction times than the participants that were in the furthest lane (Brown, Kenwell, Maraj, Collins, 2008). Once the researchers established that the reaction times differed, a study was then conducted to measure reaction times specifically but also force produced in relation to dB level of the “Go” signal. The study, Go Signal Intensity Influences the Sprint Start, came to the same conclusion of the 2004 Olympics data dealing with lane assignment and further added to the data by including that an increase in dB level or volume of the “Go” signal decreases reaction time. Observing a particular task by watching someone perform the task or by watching a video of that task being performed by the best is always a great way to analyze what needs to be improved upon. When one watches that task in slow motion, it is even easier to break down the task and eliminate unwanted movements in the task. Then, when looking for a video of a task and finding one in slow motion that shows the best person performing the task, then all that is needed to do is relate the two videos of the participants and refer to the participant with the better technique. Asafa Powell has set the world record for the 100m September 9, 2007 at 9.74 seconds and again on September 2, 2008 at 9.72. When looking for a video of the 100m sprint one would imagine that Asafa Powell would be a great example to view. The video (http://www.youtube.com/watch?v=dvC1PNoJ2‐
k&feature=PlayList&p=9E4716F49E885018&index=33) shows Powell in his ready position on the blocks, to full extension of the leading leg, to Powell moving out of the screen. The first motion that Asafa Powell makes is his body moving slightly forward before his hands begin to lift off the ground. From this position, Powell’s body begins to move upwards at his hips. His legs begin to extend, pushing his body forward. Powell’s arms also begin to move to their starting position. As Powell’s body continues to extend forward, his back leg finishes its extension phase, then begins to move forward to a hip flexion and knee flexion position. The leading leg is now pushing to accelerate the body forward. Powell’s trunk has now moved to a placement in which it is lined up with his pelvis, creating a straight line between his skull and pelvis. Powell’s arms are now in a position that is typical of a running posture being that his elbow is in a 90 degree angle. As Powell’s body is at a 45 degree angle to the ground, his leading leg is now fully extended behind him and slightly off the blocks, whereas his other leg is fully flexed and about to begin to extend for the next stride that is required for running. Powell’s torso and hind leg are lined up with each other. Our next step in the pursuit of the understanding of what is happening during a sprint start was to determine what muscles are being used in each phase. The muscles used in each phase determine velocity and acceleration for the sprinter. To demonstrate the velocity and acceleration of a sprint start, we had two sprinters each perform a thirty meter sprint out of the sprinting blocks. We timed each sprinter at five meter intervals, a total of six, to show how they accelerated throughout their sprint. The following explains our methods and the results we found through our study. Next thing to do was to determine how fast our sprinters were going through each phase. The idea behind our phase timing analysis was to video tape two different athletes sprint starts out of sprinting blocks. We wanted to see what differences there were, using the number of frames, between each sprinter in each of the four phases of the sprint start. The phases were determined due to the nature in the posture and arrangement of body parts for the sprinter. Once all the times were determined for each the sprint start phases for the participants, their efficiency, such as the unwanted motions that waste time and energy, needed to be evaluated: it is the little things that make all the difference. The video we created, Kinematics Analysis, is a motion tracking analysis, joint angle measurement and a segment inclination measurement. The motion tracking was done at each phase with a stick figure representing the sprinters movement out of the blocks. For our joint angle measurement, we chose to measure the knee angle of the front leg of the sprinter in each phase. Finally, we decided to do a segment inclination measurement of the hip movement of each phase. Methods We will be comparing two different videos of track starts that we obtained through www.YouTube.com. One of the videos is that of an Olympic sprinter that held the world record in the 100‐m sprint (until when?). The other videos that we used to compare with the Olympic sprinter are of a college track athlete and a high school track athlete. The literature reviews, Effects of muscle‐tendon length on joint moment and power during sprint starts, Go Signal Intensity Influences the Sprint Start, Physiological demands of running during long distance runs and triathlons, Applied Kinesiology, Effects of arm and leg loading on sprint performance, The relationship between maximal jump‐squat power and sprint acceleration in athletes, were used in the understanding of how the sprint starts were to be performed. With the understanding of the sprint start we then needed to look at the muscles being used in each phase. The anatomical analysis helped to determine what muscles were being used during each phase. This was done by creating a spreadsheet with each phase having its own heading and a table devoted to it. In the tables, each major joint section was determined and each muscle was listed along with its appropriate joint action and position, the muscles that were active and the contraction type associated with that muscle. In the velocity and acceleration profile, we prepared the track at Western Oregon University for our two sprinters by sectioning off the different performance distances into six equal subsections. We designated a 30 meter straight stretch of the track where the runners would have the wind (if there was any) at their backs, and then we placed orange cones at equal five meter intervals. There were a total of six different marks that we measured the time with a video camera when each sprinter crossed that mark. The participants warmed themselves up to a comfortable level in which they felt safe to perform before they ran their sprint. After we recorded each sprinter’s “split times,” we then calculated the average section velocity (Δ d/ Δ t) and the average section acceleration (Δ v/ Δ t). The phase timing analysis was done by using a Panasonic PV‐DV73 camera, to record to a mini DV tape, to video tape the sprinters. The software program used was Sony Vegas Movie Studio Platinum with a playback frame rate of almost thirty (29.97 to be specific) frames per second (f/p/s). Two different male athletes were utilized, both with very different athletic backgrounds. Sprinter one was a middle distance to long distance runner in high school track and field. Now he is an 800 meter runner at the collegiate level. Sprinter two was a 100 meter sprinter in high school track and field as well as a competitor in a few throwing competitions. Now sprinter two is strictly a hammer thrower in the collegiate level at Western Oregon University. We told each sprinter to simply do a sprint start out of the sprinting blocks while we gave the commands “On Your Marks,” “Set,” “Go.” We only had the sprinters run approximately ten meters out of the blocks. We video recorded each sprinter’s start out of the blocks and then analyzed both of their sessions. For our methods of the video kinematics, we used the computer program Microsoft Publisher to create all of the stick figures for each different analysis. For the motion tracking analysis, we took a screen shot of each phase of the sprinter from our recorded video and then copied the photo into Publisher. Next, we applied the appropriate line segments over each body segment of the copied photo in order to create the sprinter. This process was continued for each of the four total phases. We represented each joint with small circles. Since we already had created a stick figure for each of the four phases of the sprint start, it was a lot easier to complete the joint angle measurements. We decided to measure the angle of the knee of the front leg of the sprinter because it is a critical joint movement for this particular skill. (what particular skill?) We took the stick figures from our motion tracking analysis and measured the appropriate knee angle of each of the four phases. The segment inclination measurement was also created using Publisher. We used the same four screen shots from the video to determine the position and angle of the hips. Both sprinters were used for comparison of the orientation in which the hips moved through space. A triangle was used to represent the hips and the base of the triangle is supposed to represent the crest of the hips. At each phase we observed where the hips were and how they were tilted, and we moved the triangle to best represent this. A dotted line was then used to show the path the hips moved between phases. A parallel line was then placed at the lowest point of the base of the triangle to help determine the angle at which the hips are at in that particular phase. Though we determined with great accuracy where the hips were, along with their angle proportionate to a determined horizontal position, there was still room for error in the measurements. Results Sprint Start Mechanics Checklist Phase 1 Phase 2 Phase 3 "On Your Marks" Feet placed in blocks Front knee is even with the starting line but off the ground Rear knee is rested on the ground Body is leaned forward with shoulders over the starting line Hands placed in proper alignment behind the line "Set" Front leg creates a 90° angle Rear leg creates approximately 120° angle Body is leaning forward with most of the body weight on hands Arms are straight at a 75° over starting line Hips come up higher than shoulders "Go" Extension of the rear leg Arms come off the ground Body is parallel to ground Olympic 5 5 5 5 5 5 5 5 5 5 5 5 5 College 5 5 5 5 5 4 4 1 5 4 5 2 2 5 3 4 High School 5 5 5 5 5 4 4 5 5 5 5 5 5 5 Head is tucked "First Step/Front Leg Phase 4 Extension" Front foot pushing off the block Front leg in full extension Rear foot flexed towards shin Rear leg flexed Straight line between foot and head along body Body is at a 40° angle to the ground Front arm is at 90° between upper and lower arm Rear arm is at a 180° and extended above body Head is tucked Key 1 Incomplete Almost 2 Incomplete 3 Near Complete Almost 4 Complete 5 Complete 5 4 4 5 5 2 5 4 5 5 5 4 Sprint Start Beginning/Ending Point "On Your Marks" Beginning Phase 2 Phase 3 Phase 4 End Feet and hands are placed and knees are touching the ground. When the body becomes motionless waiting for the "Set" signal. "Set" Beginning Knees and hips are pressed upwards at "Set" Signal End Body becomes motionless waiting for the "On Your Marks" Signal "Go" Beginning Body begins accelerating in a linear motion on the "Go" signal End The rear foot leaves the block. "First Step/Front Leg Extension" Beginning Rear leg is in a forward motion. Front arm is in a forward motion. End Front leg is fully extended. Rear arm is extended above body. 5 5 4 5 3 6 4 5 3 7 3 5 5 5 5 5 5 5 5 5 Subscripts are critiques that are in the discussion. Phase 1 2 Comprehensive Anatomical Analysis Phase 1 "On Your Marks" Active Muscles Sternocleidomastoid Splenius Rectus Abdominus External Obliques Internal Obliques Transverse Obliques Errector Spinae Quadratus Lumborum Contraction Type All Isometric Right Side: Concentric ‐ Serratus Anterior, Pectorails Minor Eccentric ‐ Levator Scapulae, Rhomboid, Trapezuis Left Side: Concentric ‐ Serratus Anterior, Pectorails Minor Eccentric ‐ Levator Scapulae, Rhomboid, Trapezuis Right Side: Concentric ‐ Pectoralis Major,Anterior Deltoid, Coracobrachialis, Biceps Brachii Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii Left Side: Concentric ‐ Pectoralis Major,Anterior Deltoid, Coracobrachialis, Biceps Brachii Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii Joint Name Head/Neck Joint Action/ Position None Trunk Lumbar Flexion Scapula Abduction Levator Scapulae Pectoralis Minor Rhomboid Serratus Anterior Trapezius Shoulder Right Side: Flexion, Internal Rotation, Adduction Left Side: Flexion, Internal Rotation, Adduction Pectoralis Major Latissimus Dorsi Deltoid Coracobrachialis Subscapularis Supraspinatus Infraspinatus Teres Minor Teres Major Triceps Brachii Biceps Brachii Elbow Flexion Biceps Brachii Triceps Brachii Brachioradialis Brachialis Pronator Teres Anconeus Bilateral: Isometric Isometric Isometric Exhalation/Concentric Eccentric Eccentric Eccentric ‐ Triceps Brachii, Anconeus, Biceps Brachii, Brachioradialis, Brachialis, Pronator Teres Radioulnar Pronation Pronator Teres Pronator Quadratus Supinator Biceps Brachii Brachioradialis Eccentric ‐ Supinator, Biceps Brachii, Pronator Teres, Pronator Quadratus, Brachioradialis Wrist Stabilization Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis All Isometric Hip Flexion Adductor Brevis Adductor Longus Adductor Magnus Biceps Femoris Semimembranosus Semitendinosus Iliopsoas Rectus Femoris Pectineus Sartorius Gracilis Gluteus Maximus Gluteus Minimus Gluteus Medius Tensor Fascia Latae Deep 6 lateral rotators Eccentic ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Isometric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Knee Flexion Vastus Lateralis Vastus Intermedius Vastus Medialis Rectus Femoris Biceps Femoris Popliteus Semimembranosus Semitendinosus Sartorius Gracilis Gastrocnemius Eccentric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Isometric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Ankle Dorsi Flexion Soleus Gastrocnemius Tibialis Anterior Tibialis Posterior Peroneus Longus Peroneus Brevis Isometric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis, Tibialis Anterior Active Muscles Sternocleidomastoid Splenius Rectus Abdominus External Obliques Internal Obliques Transverse Obliques Errector Spinae Quadratus Lumborum Contraction Type Isometric Right Side: Concentric ‐ Serratus Anterior, Pectorails Minor Eccentric ‐ Levator Scapulae, Rhomboid, Trapezuis Left Side: Concentric ‐ Serratus Anterior, Pectorails Minor Eccentric ‐ Levator Scapulae, Rhomboid, Trapezuis Right Side: Concentric ‐ Pectoralis Major,Anterior Deltoid, Coracobrachialis, Biceps Brachii Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii Left Side: Concentric ‐ Pectoralis Major,Anterior Deltoid, Coracobrachialis, Biceps Brachii Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii Phase 2 "Set" Joint Name Head/Neck Joint Action/ Position Cervical Flexion Trunk Lumbar Flexion Scapula Abduction Levator Scapulae Pectoralis Minor Rhomboid Serratus Anterior Trapezius Shoulder Right Side: Flexion, Internal Rotation, Adduction Left Side: Flexion, Internal Rotation, Adduction Pectoralis Major Latissimus Dorsi Deltoid Coracobrachialis Subscapularis Supraspinatus Infraspinatus Teres Minor Teres Major Triceps Brachii Biceps Brachii Elbow Flexion Biceps Brachii Triceps Brachii Brachioradialis Brachialis Pronator Teres Anconeus Eccentric ‐ Triceps Brachii, Anconeus, Biceps Brachii, Brachioradialis, Brachialis, Pronator Teres Radioulnar Pronation Pronator Teres Pronator Quadratus Supinator Biceps Brachii Brachioradialis Eccentric ‐ Supinator, Biceps Brachii, Pronator Teres, Pronator Quadratus, Brachioradialis Bilateral: Eccentric ‐ Rectus Abdominus, Internal Obliques, External Obliques, Transverse Oblique Isometric ‐ Errector Spinae, Quadratus Lumborum Wrist Stabilization Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis All Isometric Hip Flexion Adductor Brevis Adductor Longus Adductor Magnus Biceps Femoris Semimembranosus Semitendinosus Iliopsoas Rectus Femoris Pectineus Sartorius Gracilis Gluteus Maximus Gluteus Minimus Gluteus Medius Tensor Fascia Latae Deep 6 lateral rotators Isometric ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Concentric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Knee Flexion Vastus Lateralis Vastus Intermedius Vastus Medialis Rectus Femoris Biceps Femoris Popliteus Semimembranosus Semitendinosus Sartorius Gracilis Gastrocnemius Isometric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Concentric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Ankle Planter Flexion Soleus Gastrocnemius Tibialis Anterior Tibialis Posterior Peroneus Longus Peroneus Brevis Isometric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis, Tibialis Anterior Phase 3 "Go" Active Muscles Sternocleidomastoid Splenius Rectus Abdominus External Obliques Internal Obliques Transverse Obliques Errector Spinae Quadratus Lumborum Contraction Type Isometric Joint Name Head/Neck Joint Action/ Position Cervical Flexion Trunk Lumbar Flexion Scapula Left Side: Abduction, Downward Rotation Right Side: Adduction, Downward Rotation, Elevation Levator Scapulae Pectoralis Minor Rhomboid Serratus Anterior Trapezius Left Side: Concentric ‐ Pectoralis Minor, Serratus Anterior Eccentric ‐ Levator Scapulae, Rhomboid, Trapezius Right Side: ‐ Eccentric ‐ Pectoralis Minor, Serratus Anterior Concentric ‐ Levator Scapulae, Rhomboid, Trapezius Shoulder Left Side: Flexion, Internal Rotation, Adduction Right Side: Extension, External Rotation, Abduction Pectoralis Major Latissimus Dorsi Deltoid Coracobrachialis Subscapularis Supraspinatus Infraspinatus Teres Minor Teres Major Triceps Brachii Biceps Brachii Left Side: Concentric ‐ Pectoralis Major, Anterior Deltoid, Coracobrachialis Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii, Biceps Brachii Right Side: Concentric ‐ Supraspinatus, Teres Minor, Infraspinatus, Triceps Brachii Eccentric ‐ Pectoralis Major, Anterior Deltoid, Subscapularis, Teres Major, Biceps Brachii Elbow Left Side: Flexion Right Side: Extension Biceps Brachii Triceps Brachii Brachioradialis Brachialis Pronator Teres Anconeus Left Side: Concentric ‐ Biceps Brachii, Brachioradialis, Brachialis, Pronator Teres Eccentric ‐ Triceps Brachii, Anconeus Right Side: Concentric ‐ Triceps Brachii, Anconeus Eccentric ‐ Biceps Brachii, Brachioradialis, Brachialis, Pronator Teres Radioulnar Pronation Pronator Teres Pronator Quadratus Supinator Biceps Brachii Brachioradialis Concentric ‐ Pronator Teres, Pronator Quadratus Eccentric ‐ Supinator, Brachioradialis, Biceps Brachii Isometric ‐ Erector Spinae, Quadratus Lumborum Eccentric ‐ Rectus Abdominus, External Obliques, Internal Obliques, Transverse Obliques Wrist Stabilization Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis All Isometric Hip Left Side: Flexion Right Side: Extension Adductor Brevis Adductor Longus Adductor Magnus Biceps Femoris Semimembranosus Semitendinosus Iliopsoas Rectus Femoris Pectineus Sartorius Gracilis Gluteus Maximus Gluteus Minimus Gluteus Medius Tensor Fascia Latae Deep 6 lateral rotators Left Side: Concentric ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Eccentric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Right Side: Eccentric ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Concentric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Knee Left Side: Flexion Right Side: Extension Vastus Lateralis Vastus Intermedius Vastus Medialis Rectus Femoris Biceps Femoris Popliteus Semimembranosus Semitendinosus Sartorius Gracilis Gastrocnemius Left Side: Eccentric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Concentric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Right Side: Eccentric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Concentric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Ankle Left Side: Planter Flexion Right Side: Dorsi Flexion Soleus Gastrocnemius Tibialis Anterior Tibialis Posterior Peroneus Longus Peroneus Brevis Left Side: Eccentric ‐ Tibialis Anterior Concentric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis Right Side: Concentric ‐ Tibialis Anterior Eccentric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis Phase 4 "First Step/Front Leg Extension" Contraction Type All Isometric Joint Name Head/Neck Joint Action/ Position Cervical Flexion Trunk Lumbar Extension Active Muscles Sternocleidomastoid Splenius Rectus Abdominus External Obliques Internal Obliques Transverse Obliques Errector Spinae Quadratus Lumborum Scapula Left Side: Abduction, Downward Rotation Right Side: Adduction, Downward Rotation, Elevation Levator Scapulae Pectoralis Minor Rhomboid Serratus Anterior Trapezius Right Side: Concentric ‐ Serratus Anterior, Pectorails Minor Eccentric ‐ Levator Scapulae, Rhomboid, Trapezuis Left Side: Eccentric ‐ Serratus Anterior, Pectorails Minor Concentric ‐ Levator Scapulae, Rhomboid, Trapezuis Shoulder Left Side: Flexion, Internal Rotation, Adduction Right Side: Extension, External Rotation, Abduction Pectoralis Major Latissimus Dorsi Deltoid Coracobrachialis Subscapularis Supraspinatus Infraspinatus Teres Minor Teres Major Triceps Brachii Biceps Brachii Left Side: Concentric ‐ Pectoralis Major, Anterior Deltoid, Coracobrachialis Eccentric ‐ Latissimus Dorsi, Posterior Deltoid, Subscapularis, Supraspinatus, Infraspinatus, Teres Minor, Teres Major, Triceps Brachii, Biceps Brachii Right Side: Concentric ‐ Supraspinatus, Teres Minor, Infraspinatus, Triceps Brachii Eccentric ‐ Pectoralis Major, Anterior Deltoid, Subscapularis, Teres Major, Biceps Brachii Elbow Flexion Biceps Brachii Triceps Brachii Brachioradialis Brachialis Pronator Teres Anconeus Concentric ‐ Biceps Brachii, Brachioradialis, Brachialis, Pronator Teres Eccentric ‐ Triceps Brachii, Anconeus Radioulnar Pronation Pronator Teres Pronator Quadratus Supinator Biceps Brachii Brachioradialis Concentric ‐ Pronator Teres, Pronator Quadratus Eccentric ‐ Supinator, Brachioradialis, Biceps Brachii Concentric ‐ Erector Spinae, Quadratus Lumborum Isometric ‐ Rectus Abdominus, External Obliques, Internal Obliques, Transverse Obliques Wrist Stabilization Flexor carpi radialis Flexor carpi ulnaris Palmaris longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis All Isometric Hip Left Side: Flexion Right Side: Extension Adductor Brevis Adductor Longus Adductor Magnus Biceps Femoris Semimembranosus Semitendinosus Iliopsoas Rectus Femoris Pectineus Sartorius Gracilis Gluteus Maximus Gluteus Minimus Gluteus Medius Tensor Fascia Latae Deep 6 lateral rotators Left Side: Concentric ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Eccentric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Right Side: Eccentric ‐ Iliopsoas, Rectus Remorus, Pectineus, Sartorius, Gracilis, Tensor Fascia Latae, Adductor Longus Concentric ‐ Adductor Brevis, Adductor Magnus, Biceps Femoris, Semimimembranosus, Semitendinosus, Gluteus Masimus, Gluteus Minimus, Gluteus Medius, Deep 6 Later Rotators Knee Left Side: Flexion Right Side: Extension Vastus Lateralis Vastus Intermedius Vastus Medialis Rectus Femoris Biceps Femoris Popliteus Semimembranosus Semitendinosus Sartorius Gracilis Gastrocnemius Left Side: Eccentric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Concentric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Right Side: Eccentric ‐ Vastus Lateralis, Vastus Intermedius, Vastus Medialis, Rectus Femoris, Sartorius, Gracilis Concentric ‐ Biceps Femoris, Popliteus, Semimembranosus, Semitendonosus, Gastrocnemius Ankle Left Side: Plantar Flexion Right Side: Dorsi Flexion Soleus Gastrocnemius Tibialis Anterior Tibialis Posterior Peroneus Longus Peroneus Brevis Left Side: Eccentric ‐ Tibialis Anterior Concentric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis Right Side: Concentric ‐ Tibialis Anterior Eccentric ‐ Soleus, Gastrocnemius, Tibialis Posterior, Peroneus Longus, Peroneus Brevis Velocity, Acceleration Analysis Velocity Acceleration Profile 30 meter sprint (cumulative) Total time(s) Displacement(m) ∆d ∆t Avg. Velocity (m/s) (∆d/∆t) ∆v (m/s) ∆t=.5(t1+t2) (s) Avg. Acceleration (m/s^2) (∆v/∆t) Sprinter 1 0 1.3 0 2.17 5 1.90 1.78 8.77 6.42398287 0.44 0.62 1.19 0.40 0.67 0.57 8.33 Overall 1.75 0.79 0.79 5 0.60 7.94 1.40 1.09 5 0.63 30 25 5 7.14 4.67 0.70 5.75 4.1 20 5 0.87 3.85 15 5 1.3 3.5 2.87 10 5 0.59 0.65 0.75 Velocity Acceleration Profile 30 meter sprint (cumulative) Total time(s) Displacement(m) ∆d ∆t Avg. Velocity (m/s) (∆d/∆t) ∆v (m/s) ∆t=.5(t1+t2) (s) Avg. Acceleration (m/s^2) (∆v/∆t) Sprinter 2 0 1.4 0 2.1 5 1.4 15 0.70 1.05 3.40 ‐1.31 0.59 1.83 7.46 6.46551724 0.44 0.65 0.00 8.77 1.19 0.70 0.67 Overall 5 0.57 8.33 0.00 30 5 0.60 7.14 3.57 25 4.64 3.97 5 0.70 7.14 20 5 3.4 3.57 2.8 5 10 5 0.62 0.75 ‐2.11 Phase Timing Analysis Phase Sprinter 1 Frames 67 36 6 5 Sprinter 2 68 42 7 4 1 2 3 4 Total Time Springer 1 Sprinter 2 Time(sec) Time(sec) 2.23 2.27 1.20 1.40 0.20 0.23 0.17 0.13 3.80 4.03 Kinematic Analysis Discussion The performers that were evaluated and compared ranged from an Olympic athlete to a college athlete to a high school athlete. When we evaluated the Olympic athlete, we ranked him with all “5s” due to the expertise and precise execution of all determined aspects of each phase. Based on our checklist, we could not determine any deviations. We found that our college athlete was not as proficient as the Olympic athlete, and therefore didn’t rank as high. The high school athlete lacked in some key aspects of each phase, as compared to the college athlete and the Olympian. We assumed that this is due to the lack of experience. After evaluating our videos, we determined that our checklist was very comprehensive on all of the key elements of a sprint start. However, there were a few things that we could have been more specific on. For example, in the “Set” phase we should have specified that the athlete should have been on their fingertips. Another slight mistake is in the “Go” phase. We needed to specify that when the arms come off the ground, they need to stay in the sagittal plane. The positive and negative critiques that we found from all three athletes are as follows: For the Olympic athlete we found no negative critiques, though we did notice some very positive key aspects of certain phases. In every phase we noticed that the athletes head was tucked and in phase 4 we noticed that his body had an excellent alignment between head and front foot. The college athlete, on the other hand, had a few negative critiques. 1.
Rear leg creates about a 100° angle instead of a 120° in phase 2. 2.
Rear leg is pulled forward with no extension in phase 3. 3.
Arms move in the frontal plane away from the body in phase 3. 4.
Head pops up and then becomes tucked in phase 3. A positive critique for the college athlete was that they had a 40° angle to the ground with their body in phase 4. Then they also had great extension of front leg off the blocks in phase 4. The high school athlete had less negative critiques than the college athlete though he didn’t perform as well overall. 5. Presses with rear leg and locks knee before they even moved forward in Phase 3. 6. Back is arched forward in Phase 4. 7. Arm is actually more at a 110° angle than a 90° which it is supposed to be in Phase 4. Positive critiques of the high school student are that he has most of their weight forward on their hands in phase 2 along with great extension of the front leg in Phase 4. The literature review gave us background information on sprint starts and the recent work that has been done. It was a starting point for this project. The anatomical analysis allowed us to see what was happening at the skeletal level to the body. Determining the differences between phases allowed for a better understanding of what each limb was doing while creating opposing moments of inertia to stabilize the body. Using phase timing for our first sprinter, that we taped, we noticed that his speed increased over each interval. This leads us to believe that this is a very well trained and well conditioned sprinter. We believe from the data from the phase timing that the thirty meters might not have been long enough for him to reach top speed. From the data and film there is nothing that we can critique with sprinter one. He had great form out of the blocks and he progressively decreased his split times. He could always practice starting out of the blocks to increase his efficiency and speed. With our second sprinter we noticed that his intervals decreased as he progressed down the track. Between the fourth and fifth cones he slowed down showing that within those five meters he reached his top speed and began to slow. A critique for sprinter two would be to keep his head down out of the blocks because keeping his head down helps decrease wind resistance. One thing that we noticed was that his hips dropped a little between the second and third phase and we believe that this is due to how close his feet are in the blocks. If he were to increase the distance between the feet placement platforms his hips could be dropped to the same height that he runs at. A training technique that sprinter two could use would be to do 200 to 400 meter sprints to increase his aerobic endurance/muscle glycogen stores. We found that sprinter one was quicker out of the blocks over all with a total time of 3.80 seconds compared to sprinter two of 4.03 seconds. It took him 67 frames, or 2.23 seconds, to finish phase one where as Sprinter two took 68 frames, or 2.27 seconds. Phase two was quicker with Sprinter one with 36 frames, or 1.20 seconds, where as Sprinter two took 42 frames, or 1.40 seconds. The third phase was much closer between the two sprinters with only a one frame difference. In the last phase Sprinter two was quicker by a frame, though over all had a slower time. Over all our subjects had very close results, in terms of frames per second, though hundredths of a second can separate first from last in a race. From observing the three different video kinematic analyses we were able to have a better understanding of the sprint start. In turn, this enables us to help sprinters, as well as ourselves, in explaining the most efficient method for a sprint start. The motion tracking analysis allowed us to see the critical movements of each phase the sprinter goes through. With this we then helped critique the sprint start of our subjects to increase their overall efficiency in their start. The knee joint angle measurement allowed us to measure the knee angles and then fine tune the sprinters start for maximum acceleration. Where as the segment inclination measurement of the hip allowed us to watch how the hip traveled in each phase. With this we were able to determine if there was any inefficient movement of the hips such as downward movement before acceleration. Knowing the angle of the hip allowed us to determine the orientation of the torso which showed where the center of gravity was during the acceleration portion of the sprint start. All three of these analyses came together to help us, and the sprinters, learn more about the sprint start and to critique the efficiency of each of the specific different phases. The three kinematic analyses show the motion of the sprinter’s bodies as they move to from phase to phase. The direction in which the body moves is determined by many different things but one that is very essential is the force which the legs create to get the body moving. Many different biomechanical principals can be applied to a sprint start. Newton’s First Law of Motion is the law of inertia. Inertia is the resistance an object has to change direction. This means that if an object is moving in a certain direction and velocity, it will resist any change to its direction or speed. This can also be looked at as anything resting will resist any change. All athletes and objects have mass, which is the amount of matter an object has, and therefore have the potential for inertia. Mass is directly related to inertia because the more mass an object has, the more inertia it has. Therefore, if someone who possesses mass and is moving in a particular direction and speed they will resist any change. So when a sprinter moves from one phase to another, the mass of the body resists the change, but once a particular body part is moving in a desired direction they try to obtain the highest amount of velocity for that segment. The push of the thighs from the blocks to move the body forward is the change of mass and inertia. One can easily demonstrate a sprint start through the use of Newton’s Second Law of Motion, which is the law of acceleration, represented in the simple formula force = mass x acceleration. In the sprint start, the sprinter extends their legs to push against their mass as well as against the earth through the use of the blocks. The sprinter accelerates in a forward direction while the earth moves a negligible amount in the opposite direction of the sprinter. The sprinter accelerates because the force produced by the sprinter’s muscles overcomes the inertia of the sprinter’s mass. To demonstrate Newton’s Second Law of Motion, one can take two sprinters of the same mass and have them apply a force for the same amount of time. The sprinter who applies the greater amount of force will accelerate quicker than the sprinter who applies less force. Newton’s Third Law of Motion is the law of action and reaction. When an athlete exerts a force on a second object, the latter will exert a reaction force on the first that is both equal and opposite in direction. The action and reaction of a sprint start is shown when the sprinter applies a muscle force by extending their legs, or exerting force, against the starting blocks. The action is the force, or push, that the sprinter applies against the blocks. The reaction to the sprinter is the equal and opposite force that the earth applies to push back against the sprinter, or the earth’s ground reaction force. Since the earth’s potential force is greater than what the sprinter can produce, the sprinter is then the object that moves. The center of gravity is the point at which the mass of an athlete is balanced in all directions and the point where the gravitational forces are centralized. The sprint start is used at a stable position that is used to get the sprinter out of the blocks as soon as possible. In the “set” command position of the sprint start, the center of gravity is low to the ground and outside of the body. The base of support is wide and long and the line of gravity is shifted close to the forward edge of the supporting base. This stance allows the sprinter’s legs to be in a powerful thrusting position and gets them into the closest position to the finish line just prior to the start. As the sprinter enters the “go” phase their base of support, or center of gravity, becomes unstable when they lift their hands off the ground. At first the sprinter uses pure gravity to give them a forward motion without using muscle contractions. This happens because the center of gravity is outside and forward of the body, which pulls the torso forward and down. After they have increased velocity for the fraction of a second, the sprinter begins to accelerate as they begin to use their muscles for movement. The sprint start is also a great example to show the impulse‐momentum relationship. Momentum is the quantity of motion that occurs with the simple formula of momentum = mass x velocity. Momentum occurs when the athlete starts their movement out of the blocks. If a sprinter increases their mass and/or velocity, they will increase their momentum. Once the momentum is initiated the impulse of the sprint start will require a massive force to be applied over a short distance and a short time frame. An impulse is the force multiplied by the time during which the force acts. A strong and flexible sprinter can apply more force over a greater time frame than a weak and less flexible sprinter. The flexible sprinter allows for a greater range of motion. This motion can be translated into the greater amount of time in which the motion is being performed. A less flexible sprinter has a shorter distance in which they can perform the task. An energy efficient movement can be created if all the training techniques, equipment, and surfaces work together in a harmonious manner. Optimal techniques are designed to decrease the amount of energy loss. The main purpose of these techniques is to decrease deformation of the body, equipment, and surfaces as well as to decrease the amount of impact upon the body. With proper use of these techniques, all extraneous movements are eliminated. Deformation of the body is decreased in knee and foot flexion with proper placement of the blocks. Deformation of equipment is decreased with the utilization of stiff, very thin soled, and very light shoes. Deformation of surface occurs with the spikes of the shoes. The spikes create more traction for the sprinter by penetrating the track and decreasing friction because of the surface area of the spikes and the material with which the spikes are made. Impact is increased due to the decreased amount of sole of the shoes but is combated with the track material. Having a tucked head, arms moving in the sagittal plane, and having flexed hips and knees are all ways to decrease extraneous movements. We gained an immense amount of knowledge about the sprint start and if time were allowed, much more could have been obtained. Strengths of this project were that in this modern age all of the different technology that are available to us made it possible to evaluate the sprint start in a much more efficient manner than could have otherwise been done. A weakness of this project was that since the movement was so fluid it was hard to make a clear determination when we were creating our phase descriptions. Future investigations could use the unclear correlation between phases to more precisely create phase descriptions by possibly extending the distance in which the start is measured. 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