Download tapering - دکتر حمید آقا علی نژاد

Tarbiat Modares University
Tapering
Hamid Agha Alinejad,PhD
1
Introduction

The taper is a training phase before competition during
which the training load is progressively reduced for a
variable period of time to allow for physiological and
psychological recovery from accumulated training stress,
with the aim of maximizing competition performance.

The relationship between the reduced training load during
the taper and performance benefits is well established,
allowing investigators to make training recommendations
to optimize pre-event tapering strategies

The aim of this lecture is to compile and synthesize the
present knowledge on tapering induced physiological
changes in athletes and assess the possible
relationships between these changes and performance
benefits of the taper.
Cardio respiratory Changes
Maximal Oxygen Uptake
Maximal oxygen uptake (VO2max) can increase or remain
unchanged during periods of taper before competition in
highly trained athletes.
Effect of the taper on maximal oxygen uptake
Decrease in VO2max during the taper would most likely be indicative of a poorly
planned tapering strategy in endurance athletes.

Neary et al(2003) have reported VO2max enhancements
of 6.0% in cyclists reducing their weekly training volume
by 50% during 7 days.

Neither an increase in VO2max nor a simulated
performance gain was observed in cyclists reducing
training volume by 30% or 80% during a 7-day taper.

The same group also reported an increase in VO2max (2.5%) and
simulated performance (4.3%) in cyclists who maintained training
intensity but reduced training volume.

In contrast, cyclists maintaining training volume but reducing intensity
only showed statistically non-significant improvements in VO2max
(1.1%) and simulated performance (2.2%).

intensity is a key factor for the maintenance or
enhancement of training-induced adaptations and
optimization of sports performance.

Jeukendrup et al (1993) – cyclists - a 4.5% increase in
VO2max, a 10% higher peak power output and 7.2% faster
8.5km outdoor time trial at the end of 2 weeks taper.

Margaritis et al (2003) – triathletes - 3% gains in both
VO2max and simulated performance during a14-day taper.

Several investigators have observed unchanged VO2max
values as a result of a taper.

Collectively, these studies generally show improved or
stable VO2max and performance gains after a taper,
particularly where training intensity has been maintained.
Economy of Movement
The economy of movement is defined as the oxygen cost
of exercise at a given submaximal exercise intensity.

Houmard et al (1994) – distance runners - a 7% (0.9
kcal/min) decrease in calculated submaximal energy
expenditure when running at 80% peak oxygen uptake
on a treadmill.

Dressendorfer et al (2002) – cyclists – no marked
improvement in economy in male cyclists tapering for 10
days.

The investigators suggested that an elevation in
the muscle’s mitochondrial capacity, along with
neural, structural and biomechanical factors could
explain improvements in economy with the taper
Cardiac Function and Dimensions
Efect of the taper on resting, maximal & submaximal heart rate

A possible explanation for the inconsistent findings could
relate to opposite effects on maximal HR of blood
volume expansion and the level of catecholamine
depletion that may have been incurred during the
preceding phase of intense training.
Cardiac Dimensions

Haykowsky et al (1998) – swimmers - no marked change
in diastolic or systolic cavity dimensions, ventricular
septal wall thickness, estimated absolute or relative left
ventricular mass, stroke volume, cardiac output, cardiac
index or fractional shortening.
Ventilatory Function

Neary et al (2003) – cyclists - Peak ventilatory volume was
unchanged but the ventilatory equivalent (VE/Vo2) for
oxygen declined.
Haematology
Balance Between Haemolysis and Erythropoiesis

Intensive athletic training can results in decreased red
blood cells, haemoglobin concentration and haematocrit
that have variously been attributed to a haemodilution
caused by training-induced expanded plasma volume,
an imbalance between haematopoiesis and intravascular
haemolysis, or iron deficiency.

Taper-induced increases in blood and red cell volume
have been reported in highly trained that associated with
an elevation of plasma renin activity and vasopressin
concentration during exercise and a chronic increase in
the water-binding capacity of the blood.

Haemoglobin concentration and haematocrit increased
during the taper that attributed to a decreased
haemolysis and a net increase in erythrocytes.
Metabolic Changes
Energy Expenditure/Energy Balance

A certain level of muscle mass loss may have taken
place during the taper and suggest that athletes tapering
for competition should pay careful attention to matching
energy intake in accordance with the reduced energy
expenditure that characterizes this training period.
Substrate Availability and Utilization

During submaximal-intensity & maximal exercise RER
values have been shown to remain unchanged after
tapering.

These results suggest that the substrate contribution is
not modified by a taper.

This lack of change may be related to stable aerobicanaerobic work production and oxygen deficit during the
taper.
Blood Lactate Kinetics
Significant relationships were seen between increases in peak post-race blood lactate
levels and competition performance enhancement (r = 0.63).
Muscle Glycogen

Muscle glycogen concentration has been shown to
increase progressively during periods of taper.
Biochemical Changes
Creatine Kinase


Blood levels of creatine kinase (CK) have been used as
an index of training-induced physiological stress.
Various studies have shown decreases in CK levels
during the taper.
Hormonal Changes
Testosterone, Cortisol and the Testosterone : Cortisol
Ratio

The plasma levels of testosterone (T) and cortisol(C) could
represent anabolic and catabolic tissue activities, respectively.
Catecholamines

Plasma and urinary catecholamine concentrations is a
means to monitor training stress & identify overreaching
or overtraining in athletes.

the change in plasma catecholamine concentration could
be a useful marker for monitoring recovery associated
with the taper.
Neuromuscular Changes
Strength and Power
 Increased strength and power as a result of a taper have
been a common observation in different athletic activities.
The mechanisms responsible for the taper induced
improvements in muscular strength and power


-
-
Changes in enzymatic activities
Muscle fibre characteristics
Muscle Fibre Size
Metabolic Properties
Contractile Properties
Immunological Changes
Many aspects of the immune system exhibit a range of
responses to acute exercise and prolonged training in
athletes preparing for competition:
-
Increased leukocyte cell counts particularly neutrophils and
lymphocyte subsets
Decreased functional activity of the neutrophil respiratory
burst
Decreased natural killer cytotoxicity
Decreased response to mitogen-induced T-lymphocyte
proliferation
Decreased concentration of mucosal immune parameters,
such as secretory immunoglobulin A
Impaired delayed-type hypersensitivity response (T-cell
function)
Unchanged or increased circulating concentration of
cytokines
Psychological Changes
Optimization of an athlete’s physiological status
resulting from a well designed tapering strategy is
presumably accompanied by beneficial
psychological changes, including:
-
Mood state
Perception of effort
Quality of sleep
Mood state
Taper planning
Reduction of training intensity

Training intensity is an essential requirement for
maintaining training-induced adaptations during period of
taper.

Mujika et al (2000): HIT during the taper correlated
positively with the percentage change in circulating T
levels in well-trained middle- distance runners.
Reduction of training volume

Standardized training volume reduction of 50-70% have
been shown to be a valid approach to retain or slightly
improve training-induced adaptations in well-trained
athletes.
Reduction of training frequency

For moderately trained individuals 30-50% and for
highly trained athletes, much higher training
frequency, >80% of pretaper values, should be
recommended, especially in the more “techniquedependent” sports such as swimming.
Duration of the taper

Duration of a taper for individual athlete is one of the
most difficult challenges for coaches and sports
scientists.

Positive physiological, psychological & performance
adaptations have been reported as a result of taper
programs lasting 4-14 d in cyclist & triathletes, 6-7 d in
middle- and long-distance runners, 10 d in strength
trained athletes & 10-35 d in swimmers.