Download Elbow Joint Position Sense

A PRELECTION ON:
Effects of Functional Fatigue on Position Sense of Elbow and
Shoulder Joints in Elite Female Table Tennis Players with Upper
Crossed Syndrome
Presented By:
2nd International Conference and Expo on Novel Physiotherapies
BRIEF CONTENTS
NO
TITLE
1
Introduction
2
Materials and Methods
3
Results
4
Conclusions

Upper crossed syndrome is a kind of musculoskeletal involvement that
affects upper back and neck muscles leading weakness of the muscles and
to strengthen the others.

This muscle imbalance leads to abnormalities in the person's forward head
and rounded shoulders.

Several investigations have expressed the overall prevalence of UCS in the
range of 34% to 42% among table tennis players.

In this field of sport as other fields, in exercises and tournaments, the
athletes take an especial physical form that may predispose the body to
postural abnormalities and deviations for a long time.

The concept of proprioception was primarily introduced by Sherrington in 1906
as a feedback from the nerves to the central nervous system.

Proprioception is a kind of the sense of touching. Pacinian corpuscles, ruffini
organs, muscle spindles and Golgi tendon organs are mechanoreceptors that
transfer mechanical changes as neural impalses through myelinated neural
fibers from dorsal spinal root to central nervous system.

This sense has important roles such as participating in the accurate
movements by neuromuscular control as well as joint stability through creating
muscle reflexes.

Thus, the presence of poor proprioception and the weakness of these two
functions, the increased risk for injury are expected. The studies could show
that most injuries caused by table tennis playing are observable in two zones of
elbow and shoulder girdle.

Several studies have been conducted on the effects of fatigue on athletic
performance, but it seems that most of the fatigues were not functional and
also there was not a correlation between fatigue and specific sports skills.

Also, most studies have been performed on healthy individuals without
abnormalities or with emphasis on functional fatigue.

Hence, the present study aimed to assess the effects of functional fatigue as a
risk factor for injury on position sense at the elbow and the shoulder girdle
joints in the elite female table tennis players with upper crossed syndrome and
also to compare with healthy players.
Participants
This semi-experimental study was performed on 24 elite
female table tennis players participating in the students
Olympiad in 2014.

All participants provided written informed consent to take part
in this study.
The research was approved by the ethical committee of the
Institute of Research Management and Monitoring, Shahid
Bahonar University of Kerman Research Committee.

Procedure
The study was conducted to evaluate upper crossed syndrome in eligible
subjects by taking pictures with camera (SONY CyberShot WX350,
Japan) from a distance of 3 meters with light clothing and standing from
lateral view with a camera angle of 90 degrees.
In this regard, the presence of upper crossed syndrome was diagnosed
based on forward head angle or FHA (determined by measuring the
angle between a line drawn from the tragus to the C7 spinous process
and a vertical plumb line through C7) and rounded shoulders angle or
RSA (by measuring the angle between a line drawn from the tip of the
acromion process to the C7 spinous process and a vertical plumb line
through C7) based on the FHA higher than 46 degrees and RSA higher
than 52 degrees.
Procedure
For assessing position sense at the elbow, in the flexor taut
condition, elbow flexors were contracted with the arm held
at 45°. After maintaining flexion for 5 seconds, subjects
were asked to relax the arm and kept in mind the point.

Then, the patients were asked to return the arm to the original
position and then back again at the same point. The
difference between the target angle and reconstructured
angle was calculated as the absolute error using the
photography of hand side view with the camera angle of 90
degrees and a distance of 3 meters by AutoCAD software.



Elbow Joint Position Sense
For assessing position sense at the elbow, in the flexor taut
condition, elbow flexors were contracted with the arm held
at 45°. After maintaining flexion for 5 seconds, subjects
were asked to relax the arm and kept in mind the point.
Then, the patients were asked to return the arm to the
original position and then back again at the same point.
The difference between the target angle and
reconstructured angle was calculated as the absolute error
using the photography of hand side view with the camera
angle of 90 degrees and a distance of 3 meters by AutoCAD
software.



Shoulder Joint Position Sense
For assessing position sense at the shoulder, after marking ulnar bone
and olecranon processes, the patient was asked to position arm and
elbow at 90 degrees when lying on the bed. After closing the eyes using
blindfolded, the patient was asked to slowly rotated arm internally to 45
degrees.
Then, the position was maintained constant and then asked to keep in
mind the point. Then, the subject was asked to return arm to the
original position and then back again on the same point. The difference
between the target angle and reconstructured angle was calculated as
the absolute error using the photography with the camera angle of 90
degrees and a distance of 3 meters by AutoCAD software.



Fatigue Protocol
Before fatigue protocol and in order to prevent injuries, the players asked to begin warm
up for 10 minutes to general movements (stretching), following 10 minutes warming up
with specific movements (move looped forehand). This protocol was primarily designed by
Aune specifically for table tennis.
In this protocol, patients called to turn thrown ball with the utmost precision and speed to
a circular target on the opposite side of the net with a forehand technique. The patients
said to return the rockets back to the starting position before each hitting. After
performing each hit, a thrown ball moving in the opposite direction, and again returned to
the original position to hit the next shot. The players moved to the opposite side of the ball
thrown and returned again to the initial place to take the next shot. All balls were thrown
to them by the balls float in a fixed location. The protocol consisted of four 4-minute
stages that the frequency of throwing balls increased at each stage in order to increase
the load. To ensure the fatigue level, the Borg scale test was used. Every 2 minutes, the
subjects were asked to express their true feelings about the activity. The level of this scale
ranged from at least 6 (very comfortable) to a maximum of 20 (very heavy), respectively.
After creating functional fatigue, all the tests were reassessed and the data was recorded
as a post-test.

Statistical Methods

To determine the normal distribution of data and homogeneity of variances Shapiro and
Lyon tests were used.

The Mixed Repeated Measure ANOVA test was used to assess the change in position
sense after compared to before fatigue protocol. If significancy of χ2 value in Mauchly’s
Test (p ≤ 0.05), the multivariate test (Wilks's lambda) was used, otherwise, the tests of
Within-Subjects Effects (Greenhouse-Geisser corrected values for any effects) was
considered.

The effect size of each data was assessed by partial eta squeard and considered as small
effect (η2= 0.01), medium effect (η2= 0.06), and large effect (η2= 0.14). P values of 0.05
or less were considered statistically significant.
Heathy group
(n = 12)
Abnormal group
(n = 12)
p-value
Age(year)
25.08 ± 3.10
24.25 ± 3.46
0.54
History of exercise (year)
13.41 ± 1.97
12.33 ± 2.53
0.25
Height(cm)
164.5 ± 4.42
162.16 ± 14.68
0.22
Weight(kg)
53.08 ± 4.77
54.16 ± 3.85
0.54
BMI(kg/m2)
19.63 ± 1.68
20.69 ± 2.00
0.17
FHA(degree)
49.08 ± 1.97
60.08 ± 2.96
0.001
RSA(degree)
40.08 ± 1.97
49.58 ± 2.53
0.001

The two examined groups of players were matched in baseline characteristics
including mean age, body weight and height, mean body mass index, and history of
sport.

However, those players with the abnormality of upper crossed syndrome had
significantly higher mean FHA and RSA values. The repeated measure test showed
that the group with upper crossed syndrome experienced higher increase in position
sense at the elbow following fatigue protocol compared to healthy players (5.58
degrees versus 2.38 degrees, main effect of 0.67, p < 0.001).

Also, the results showed no significant difference in the mean of angle
reconstruction error between the two groups with and without abnormality after
fatigue protocol before that (9.58 to 6.75 in group with upper crossed syndrome and
9.00 to 6.58 in healthy group, main effect of 0.01, p = 0.53).

The exact mechanism that affects joint position sense is not clear yet, but
several possible mechanisms that may have an impact on this condition.

Studies have shown that increased joint laxity after fatigue may be involved
in changes in joint position sense. It has been shown that fatigue increases
the laxity around the hip joint ligaments (Nawata et al. 1999) and
consequently despite the increased joint laxity, joint position sense may be
decreased (Rozzi et al. 1999).

The second mechanism is the possible environmental effects on fatigue
receptors. The relative role of each joint and muscle receptors in joint
position sense impairment after functional fatigue still remains
controversial.

In general, several reports have shown that fatigue has a greater effect on
muscle receptors than the joint receptors.

Thus, the losing sense may be due to losing the inputs of muscle receptors
(Hiemstra et al. 2001). In 2006, Allen and colleagues studied the effect of
fatigue on sense of elbow. In this study, the fatigue protocol was applied to
both introvert and extrovert indicating increase in angle reconstruction error
at the elbow. The rate for this increase was the same after the introvert and
extrovert exercise (Allen et al. 2006).

Walsh and colleagues have also reported that the exercise-induced fatigue
could decrease the position sense at the elbow that was higher after
extrovert exercises than in introvert exercises (Knox & Hodges, 2005).

Generally, fatigue reduces muscle power production as well as impairs
neuromuscular coordination. It was also reported that fatigue impairs
proprioceptive receptors, especially the activity of the muscle spindles and
Golgi tendon organ and also reduces the sensitivity of transferring nerve
messages (Hiemstra et al. 2001).

Also, studies have shown that any change in the head and neck due to the
disruption in integrating sensory information from the vestibular systems,
visual and sensorimotor systems reduces the sense of the elbow (Proske et
al. 2000).

Less reconstruction error in the groups after fatigue suggests that people
can coordinate fatigue with proprioceptive mechanisms. In fact, in the
presence of fatigue, the speed of the stimulation ofmuscle spindles and
neurons at motor cortex may bedecreased leading more injury in
proprioception.

Another possible factor for the results of this study, the method used to
measure the position sense. In our study, elbow joint position sense was
measured in space and without contacting the object or any surface,
whereas the sense of the shoulder was measured in contact with the
surface. This contact can be used as a guide to help the reconstruction
angle.
The results of this study showed that fatigue can
decrease proprioception in the elbow joint, but this
reduction was not seen in shoulder so the shoulder joint
position sense was increased. Muscle imbalance,
fatigue and reduced proprioception have been identified
in many studies as factors causing injury and thus
players should performed corrective exercises in order
to prevent damage as well as to improve proprioception.
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