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Valoración del paciente: Diagnóstico del
Laurent BOSQUET1 & Iñigo MUJIKA2
1Faculty of Sport Sciences, University of Poitiers, France
2Department of Physiology, Faculty of Medicine and Odontology, University of the Basque Country, Leioa, Basque Country
Laurent BOSQUET & Iñigo MUJIKA
Iñigo Mujika earned Ph.D.s in Biology of Muscular Exercise (University of Saint-Etienne, France) and Physical Activity
and Sport Sciences (University of e Basque Country). He is a Level III Swimming and Triathlon Coach. His research
interests include training methods and recovery, tapering, detraining and overtraining. He has performed extensive
research on the physiological aspects associated with endurance sports performance, published over 80 articles in peer
reviewed journals, two books and 13 book chapters, and given over 160 lectures in international conferences. Iñigo was
Senior Physiologist at the Australian Institute of Sport, physiologist and trainer for Euskaltel Euskadi cycling team, and
Head of Research and Development at Athletic Club Bilbao football club. He is Director of Physiology and Training
at USP Araba Sport Clinic, Physiologist of the Spanish Swimming Federation, Associate Editor for the International
Journal of Sports Physiology and Performance, and Associate Professor at the University of the Basque Country.
Laurent Bosquet earned a Ph.D. in Physical Activity Sciences from the University of Montreal (Canada) and a Ph.D.
in Sport Sciences from the University of Poitiers (France). A former Professor at the University of Montreal, Laurent is
a Professor at the University of Poitiers and the Dean of the Faculty of Sport Sciences. His research interest focuses on
the optimization of training methods for dierent populations, including elite athletes, elders or patients suering from
heart diseases. He is the head of the MOVE laboratory (University of Poitiers), associate researcher at the Montreal
Institute of Geriatrics, associate researcher at the Rehabilitation Center of the Montreal Heart Institute, and member of
the research board at the French Soccer Federation.
Iñigo MUJIKA, Ph.D.
Laurent BOSQUET, Ph.D.
Endurance performance represents a complex interplay
between several physiological factors, including maximal
oxygen uptake (VO2max), aerobic endurance (AE) and the
energy cost of running (Cr) (Di Prampero et al., 1986).
Endurance training consists therefore in implementing
exercise protocols that will enhance at least one of these
determinants, in order to increase overall performance.
According to the principle of reversibility, training induced
physiological adaptations are transitory and may disappear
when the training load is not sucient. e reasons for
such a scenario are numerous in an athlete’s life: illness,
injury, post-season break or training load adaptation to
recover from a state of overreaching. e consequences
on endurance performance may vary according to the
way training load is altered: training reduction, training
cessation or bed rest connement (Mujika & Padilla, 2000a).
To avoid any confusion with the terminology, a glossary
is given in Table 10.1. is chapter addresses the eect
of training cessation on the physiological determinants
of endurance performance and their underlying factors.
Considering that detraining characteristics may dier
according to the training background, we focus on studies
dealing with well trained to highly trained athletes.
Chapter 10
Laurent BOSQUET1 & Iñigo MUJIKA2
1Faculty of Sport Sciences, University of Poitiers, France
2Department of Physiology, Faculty of Medicine and Odontology, University of the Basque Country, Leioa, Basque Country
Detraining A partial or complete loss of training induced anatomical, physiological and performance
adaptations, as a consequence of training reduction or cessation.
Training cessation A temporary discontinuation or complete abandonment of a systematic program of physical
Training reduction A progressive or nonprogressive reduction of the training load during a variable period of
time, in an attempt to reduce the physiological and psychological stress of daily training.
Table 10.1. Glossary.
Maximal Oxygen Uptake
Maximal oxygen uptake represents the maximal amount of
oxygen that can be used at the cellular level for the entire
body. It represents the upper limit of the cardiorespiratory
system and has long been considered as an important
determinant of endurance performance (Saltin & Astrand,
1967). According to the Fick principle, any alteration in
VO2max is the consequence of a modication of maximal
cardiac output (Qmax) and/or maximal arteriovenous
dierence in oxygen (a-vDO2max). It is generally accepted
that the largest part of the training induced increase in
VO2max results from an increase in blood volume, stroke
volume and ultimately Qmax. Nevertheless, the increase in
a-vDO2max, which results from a more eective distribution
of arterial blood from inactive to active muscles together
with a greater oxygen extraction and utilization capacity
by these muscles, plays also an important role in
cardiorespiratory adaptations to endurance training.
Coyle et al. (1984) studied the eect of 12, 21, 56 and 84
days of training cessation on VO2max and its determinants
in 7 well-trained cyclists. Main results are summarized in
Laurent BOSQUET & Iñigo MUJIKA
Figure 10.1. ey observed a ~15% decrease in VO2max that
followed a roughly exponential kinetics. Very interestingly,
there appeared to be a time sequence in the physiological
mechanisms underlying this loss of adaptation. During a
rst phase lasting 21 to 28 days, a-vDO2max was maintained,
suggesting that the decrease in VO2max was mainly a
consequence of a decrease in oxygen delivery to the muscle.
In fact, Coyle et al. (1985) reported a rapid decrease in
Qmax (~8%) that reached a plateau aer 21 to 28 days of
training cessation. is loss of adaptation resulted from an
important drop in maximal stroke volume (~11%), which
was partly compensated for by a ~5% increase in maximal
heart rate.
e rapid decrease in blood volume aer the rst days of
training cessation observed in several studies is expected
to play a key role in the cascade of events leading to the
decrease in Qmax (Figure 10.2). Once this rst “circulatory
detraining” phase is completed, the ongoing decrease of
VO2max is now the consequence of a continuous decrease in
a-vDO2max (~9%; Figure 10.1). Considering that capillary
density did not decline during the 84 days of training
cessation, this alteration is likely to be the consequence of a
decrease in muscle mitochondrial density or other factors
such as a reduction in muscle blood ow or capillary transit
time (Coyle et al., 1984).
In summary, these results suggest the existence of two
distinct phases in the physiological mechanisms underlying
the continuous decrease in VO2max that is observed in well-
trained endurance athletes once they stop training. During
a rst phase lasting 21 to 28 days, the decrease in VO2max is
mainly the consequence of a loss of central adaptation, as
Figure 10.1. Eect of training cessation on the physiological
determinants of maximal oxygen uptake (VO2max). Q: cardiac
output; a-vDO2: arteriovenous dierence in oxygen; SV: stroke
volume; HR: heart rate. Adapted from the data reported by Coyle
et al. (1984).
Figure 10.2. Eect of training cessation on the blood volume.
shown by a drop in Qmax, while it is peripheral (i.e. specic
to the trained muscles) aerwards. is time sequence has
many practical implications for athletes and coaches that
are discussed at the end of this chapter.
Aerobic Endurance
Aerobic endurance represents the capacity to sustain a high
fraction of VO2max throughout the entire eort duration
(Bosquet et al., 2002). Aerobic endurance is independent
from VO2max, since two individuals with the same VO2max
are not necessarily able to sustain the same fraction of
VO2max for a given eort duration (Peronnet & ibault,
1989). Both factors contribute to set exercise VO2, which
is considered an important determinant of endurance
performance, since the higher the exercise VO2, the higher
the energy provision in the form of ATP resynthesis rate.
Although physiological mechanisms involved in aerobic
endurance are not fully understood, the capacity to sustain
a high fraction of VO2max for a given duration has been
associated with a combination of several factors, including
a high percentage of type I muscle bres, the capacity to
store large amounts of muscle and/or liver glycogen, a high
activity of mitochondrial enzymes and the capacity to spare
carbohydrate by using more fatty acids as energy substrate
(Bosquet et al., 2002).
It is well established that endurance training results in an
increased percentage of type I muscle bres (Pette, 1984). It
is worth noting however that this progressive shi requires
a signicant period of time to take place and the magnitude
of change is oen small (Pette, 1984). As expected, the
eect of training cessation on muscle bre distribution
depends on the duration of the period of inactivity (Mujika
& Padilla, 2001b). While short-term training cessation (i.e.
three weeks or less) is not enough to induce any changes
(Hortobagyi et al., 1993; Houston et al., 1979), long term
inactivity periods (up to several years) have been associated
with a progressive return to baseline (Coyle et al., 1984;
Larsson & Ansved, 1985).
Non-proteic respiratory exchange ratio (RER) is commonly
used to estimate the respective contribution of fatty acids
and glucose to energy production (Péronnet & Massicotte,
1991). Endurance training has long been associated with
a reduced RER at both maximal and submaximal exercise
intensities, thus suggesting a reduced reliance on glucose
for energy production. Training cessation results in a rapid
increase in RER that appears to reach a plateau within 14
days (Figure 10.3), as well as a rapid decrease in muscle
glycogen stores (up to 20% within 1 week of bed rest or
training cessation) (Costill et al., 1985; Mikines et al.,
1989). e rapid decrease in the glucose transporter
protein GLUT-4 concentration reported aer 6 to 10 days
of training cessation (Vukovich et al., 1996), together with
the important drop of glycogen synthase activity aer just
5 days of training cessation (Mikines et al., 1989) is thought
to play a major role in this process (Mujika & Padilla,
2000a; Mujika & Padilla, 2000b).
Endurance training increases the number and size of
the muscle bre mitochondria, as well as the activity of
oxidative enzymes (Abernethy et al., 1990). One of the
main characteristics of muscular detraining is an important
decrease of this activity (Mujika & Padilla, 2001b). Coyle
et al. (1984, 1985) reported that citrate synthase activity
declined by 23% during the rst 3 weeks of training
cessation in endurance trained athletes, by 23% again from
the 4th to the 8th week and stabilized thereaer. Succinate
Figure 10.3. Eect of training cessation on the respiratory
exchange ratio during exercise. RER: respiratory exchange ratio.
dehydrogenase and malate dehydrogenase followed the
same pattern of disadaptation (Coyle et al., 1984; 1985).
Similar results have been observed in runners (Houmard
et al., 1992; Houston et al., 1979), triathletes (McCoy et
al., 1994) or soccer players (Amigó et al., 1998). Simsolo
et al. (1993) also observed a large reduction of muscle
lipoprotein lipase activity aer two weeks of training
cessation in 16 endurance athletes, which undoubtedly
altered the capacity to spare carbohydrate by using more
fatty acids as energy substrate.
e lactate concentration to a given submaximal exercise
intensity is one of the numerous methods used to
determine aerobic endurance (Bosquet et al., 2002). e
lower its concentration, the better the aerobic endurance.
Considering the short and long term loss of adaptation that
aect some of the physiological factors underlying aerobic
endurance, it is expected that this important determinant
of endurance performance is altered by training cessation.
As shown in Figure 10.4, blood lactate concentration
increases exponentially with training cessation duration,
suggesting that aerobic endurance decreases rapidly when
the training process is interrupted. Although a steady state
value is reached around 21 to 28 days, one can expect a
further decrease in aerobic endurance that results from the
progressive decrease of type I muscle bres.
In summary, aerobic endurance decreases very rapidly
once training ceases, most probably for metabolic reasons.
An additional and delayed decrease remains possible when
the duration of training cessation is long enough to alter
muscle bre distribution.
Figure 10.4. Eect of training cessation on the blood lactate
concentration during exercise.
Laurent BOSQUET & Iñigo MUJIKA
Energy Cost of Locomotion
e energy cost of locomotion (Cr) represents the energy
demand to move at a given submaximal power output or
speed. e lower the Cr, especially when body mass is
accounted for such as in running, the lower the energy
expenditure to move at a given velocity and the better
the endurance performance. Factors aecting Cr are
numerous and have been thoroughly reviewed by Saunders
et al. (2004). Some of them are not changeable (e.g. height),
while others can be manipulated (e.g. stride biomechanics,
strength, elastic store-recoil capacity). Numerous
interventions such as plyometric (Berryman et al., 2010) or
high intensity interval training (Saunders et al., 2004) are
eective to decrease Cr and improve performance.
In addition to VO2max and its determinants, Coyle et
al. (1985) also examined the response to submaximal
intensity exercise aer 12, 21, 56 and 84 days of training
cessation. Interestingly, the VO2 response for the same
absolute intensity remained stable during this period,
suggesting that the energy required to develop this power
output was not aected by the lack of training. is is in
agreement with the nding by Houmard et al. (1992) that
Cr was not altered by a 14-day training cessation period in
12 distance runners. As already mentioned, the ability to
store and recoil elastic energy as well as maximal strength
are recognized as important determinants of Cr (Saunders
et al., 2004). We recently performed a meta analysis to
examine the eect of training cessation on maximal force
and maximal power and found that both neuromuscular
qualities could be maintained for up to 3-4 weeks before
declining. is ability to maintain strength performance is
probably related with the ability to maintain Cr.
However, it is important to keep in mind that although
the oxygen demand remains stable, the strategy used
by the subjects to match this energy demand changed
signicantly over time, since the RER increased linearly
with the duration of training cessation (from 0.93 ± 0.01 at
baseline to 1.00 ± 0.01 at day 84, corresponding to a ~8%
dierence). Considering the decrease in VO2max we already
discussed, the relative intensity of this power output
increased with the duration of training cessation from 74
± 2% at baseline to 90 ± 3% at day 84 (~22% dierence).
Perceived exertion logically increased from 12.3 ± 0.4 at
baseline to 17.1 ± 0.4 at day 84 (~39% dierence). In view
of the increase in RER and likely concomitant decrease
in glycogen stores (see the preceding section), one can
easily hypothesize that although Cr is not aected, time to
exhaustion at a given intensity is signicantly altered.
In summary, the oxygen uptake required to run at a given
speed does not appear to be altered by training cessation.
However the concomitant increase in RER and decrease in
VO2max result in a decreased exercise tolerance at a given
speed, since it corresponds to a higher relative intensity
and more glucose is needed for ATP resynthesis while the
glycogen stores are markedly decreased.
Practical Implications
Previous sections described the consequences of training
cessation on the physiological determinants of endurance
performance. It is important for coaches to know whether
an alternative training strategy is ecient to limit these
consequences, particularly when the athlete is injured.
As already discussed, the factors underpinning the
continuous decrease of VO2max depend on the duration
of training cessation. ey are mainly central Qmax during
the rst 3-4 weeks, and mainly peripheral a-vDO2max
aerwards. Considering that central adaptations and
disadaptations are not specic to the trained muscles,
an alternative training can be implemented to avoid or
limit detraining while an athlete is injured. Deep water
running has been shown to be eective for this purpose
(Chu & Rhodes, 2001). For example, Bushman et al. (1997)
found that VO2max, Cr, aerobic endurance and ultimately 5
km performance could be maintained in 11 well-trained
runners who substituted their usual on-land training by
deep water running for a period of 4 weeks. One leg cycling
represents another exercise modality that can be used to
limit the central eect of training cessation in injured
athletes. Olivier et al. (2010) randomized 24 soccer players
with anterior cruciate ligament reconstruction in a control
group that followed a classic rehabilitation program and
an experimental group that added aerobic training of the
untreated leg to the rehabilitation program. Stroke volume
and VO2max were maintained in the experimental group
while they decreased by ~20 and 10% respectively in the
control group. Arm cranking represents an alternative
modality of cardiovascular training that is commonly used
in the conditioning of spinal cord injury patients (Figoni,
1990). Considering that arm VO2max represents roughly
70 to 80% of leg VO2max (Secher & Volianitis, 2006), arm
cranking allows to reach exercise intensities that should be
high enough to maintain (or limit the decrease of) Qmax.
Pogliaghi et al. (2006) provided data that tended to conrm
this hypothesis, since they found in 12 healthy men aged
67 ± 5 years that arm cranking and leg cycling were equally
eective in improving maximal and submaximal exercise
capacity, and that roughly 50% of this improvement was
due to central adaptations. It should be noted however
that arm cranking appears to be less well tolerated by
athletes than one leg cycling (Olivier et al., 2008). While
other modes of locomotion than the sport-specic one
can also be used as alternative exercises, it is worth noting
that transfer eects between modes are sometimes limited,
particularly when cycling or running are substituted by
swimming (Tanaka, 1994).
Metabolic consequences of training cessation occur rapidly
and aect both substrate utilization and glycogen stores
(Mujika & Padilla 2001a). ese adaptations are peripheral
(i.e. specic to the trained muscles). If it is possible to
implement an alternative training including exercises
that involve the same muscle groups than the competitive
activity, for example deep water running for an athlete
who suers an ankle sprain or an Achilles tendinosis, then
metabolic adaptations should be maintained. Otherwise,
athletes can eventually maintain their VO2max if an
alternative training including exercises that are not specic
to their sport specic muscle groups is implemented,
but their aerobic endurance will dramatically decrease.
Consequently, care should be taken to increase the training
load progressively when athletes resume training, since
they may eventually be able to maintain the same intensity
than before their injury, but not the same volume at this
intensity. Finally, when it is not possible to mobilize trained
muscles for a period longer than 3 to 4 weeks, peripheral
disadaptations will occur and require going through
previous training cycles to restore initial adaptations.
performance decline rapidly once the training process
is interrupted, leading to detraining and impaired
performance capacity.
athletes and coaches to implement alternative strategies
limiting the eect of training cessation.
t 702max decreases exponentially with the duration of
training cessation.
t 2max is altered before a-vDO2max, with a cut o duration
of 3-4 weeks.
negatively aect aerobic endurance.
cessation than other determinants of endurance
periods of training cessation lasting 3-4 weeks or longer.
because of an injury, athletes and coaches should estimate
the physiological consequences of implementing no
alternative training.
according to the cause of training cessation and its
anticipated duration.
duration of training cessation is short.
disadaptations will occur which require the training
program to go back to the preceding cycle.
Laurent BOSQUET & Iñigo MUJIKA
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... It has also been shown that long-term inactivity may promote a decline in cardiac dimensions and ventilatory efficiency, affecting both _ VO 2 max and endurance performance of athletes (Giada et al., 1998;Mujika & Padilla, 2000b). The decline in _ VO 2 max is mainly a consequence of a decrease in oxygen delivery to the muscle (Bosquet & Mujika, 2012). The rapid decrease in blood volume after the first days of training cessation probably plays an important role in the cascade of events that reduces maximum cardiac output, and consequently _ VO 2 max (Bosquet & Mujika, 2012;Coyle, Hemmert, & Coggan, 1986;Coyle et al., 1984). ...
... The decline in _ VO 2 max is mainly a consequence of a decrease in oxygen delivery to the muscle (Bosquet & Mujika, 2012). The rapid decrease in blood volume after the first days of training cessation probably plays an important role in the cascade of events that reduces maximum cardiac output, and consequently _ VO 2 max (Bosquet & Mujika, 2012;Coyle, Hemmert, & Coggan, 1986;Coyle et al., 1984). In the present study, the analysis of the haematological variables suggests a decrease in blood volume because of declines in red blood cell count (−6.6 ± 4.8%) and haemoglobin (−5.4 ± 4.3%). ...
... Given that improvements from retraining after training cessation take considerably longer to achieve than losses from detraining (Godfrey et al., 2005), there is a need to programme some endurance stimuli during the off-season period to minimise losses in physiological and performance measures in top-level cyclists. It is clear that during the break after the competition season, an alternative training stimulus including exercises that involve the same muscle groups as the competitive activity are necessary to maintain the metabolic adaptations to training (Bosquet & Mujika, 2012). ...
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In cycling, it is common practice to have a break in the off season longer than 4 weeks while adopting an almost sedentary lifestyle, and such a break is considered to be long-term detraining. No previous studies have assessed the effect of training cessation with highly trained young cyclists. The purpose of the present investigation was to examine effects of 5 weeks of training cessation in 10 young (20.1 ± 1.4 years) male road cyclists for body composition, haematological and physiological parameters. After training cessation, body mass of cyclists increased (P = 0.014; ES = 0.9). V_O2max (L ·min−1 = −8.8 ± 5.0%,mL · kg−1·min−1 = −10.8 ± 4.2%,), Wmax (W = −6.5 ± 3.1%, W · kg−1 = −8.5 ± 3.3%,), WLT1 (W = −12.9 ± 7.0%, W · kg−1 = −14.8 ± 7.4%,), WLT2 (W = −11.5 ± 7.0%, W · kg−1 = −13.4 ± 7.6%,) and haematological (red blood cells count, −6.6 ± 4.8%; haemoglobin, −5.4 ± 4.3% and haematocrit, −2.9 ± 3.0%) values decreased (P ≤ 0.028; ES ≥ 0.9). Five weeks of training cessation resulted in large decreases in physiological and haematological values in young top-level road cyclists suggesting the need for a shorter training stoppage. This long-term detraining is more pronounced when expressed relative to body mass emphasising the influence of such body mass on power output. A maintenance programme based on reduced training strategies should be implemented to avoid large declines in physiological values in young cyclists who aspire to become professionals.
The existing Coronavirus disease (COVID-19 outbreak has become the chief health concern all over the world. This universal epidemic with high morbidity and mortality rate affected the sports world as well as other fields of human life. In this situation, the routine and professional training of soccer players has been canceled. alterations in the training features including frequency, volume, and intensity might result in fitness detraining which will definitely have unpleasant effects on their professional life, including alterations in their physiological traits and performance. The purpose of the current study is to shed light on the probable effects of the COVID-19 epidemic detraining on athletes, in order to persuade coaches and athletes pay more attention to detraining unpleasant effects and make appropriate decisions, and employ effective strategies to reduce and prevent these effects and return to full fitness.
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In December of 2019, there was an outbreak of a severe acute respiratory syndrome caused by the Coronavirus 2 (SARS-CoV-2 or COVID-19) in China. The virus rapidly spread into the whole World causing an unprecedented pandemic and forcing governments to impose a global quarantine, entering an extreme unknown situation. The organizational consequences of quarantine/isolation are: absence of organized training and competition, lack of communication among athletes and coaches, inability to move freely, lack of adequate sunlight exposure, inappropriate training conditions. Based on the current scientific, we strongly recommend encouraging the athlete to reset their mindset to understand quarantine as an opportunity for development, organizing appropriate guidance, educating and encourage athletes to apply appropriate preventive behavior and hygiene measures to promote immunity and ensuring good living isolation conditions. The athlete's living space should be equipped with cardio and resistance training equipment (portable bicycle or rowing ergometer). Some forms of body mass resistance circuit-based training could promote aerobic adaptation. Sports skills training should be organized based on the athlete's needs. Personalized conditioning training should be carried out with emphasis on neuromuscular performance. Athletes should also be educated about nutrition (Vitamin D and proteins) and hydration. Strategies should be developed to control body composition. Mental fatigue should be anticipated and mental controlled. Adequate methods of recovery should be provided. Daily monitoring should be established. This is an ideal situation in which to rethink personal life, understanding the situation, that can be promoted in these difficult times that affect practically the whole world.
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The aim of the study was to investigate the seasonal variation in isokinetic strength of the knee flexors and extensors, and conventional (H/QCONV) and functional (H/QFUNC) hamstring to quadriceps strength ratios in highly trained adolescent soccer players. The players (n=11; age 17.8±0.3) were measured at the end of the competitive season (autumn), at the beginning and the end of pre-season (winter) and during the sixth week of a new competitive season. Isokinetic peak torque (concentric and eccentric) was measured at 60°·s-1 in a sitting position with the hip flexed at 100°. The testing range of motion was set from 10 - 90° of knee flexion. The players performed a set of five maximum repetitions for both the dominant and non-dominant leg. Statistically significant differences (p<0.001) between the four seasonal measurements were noted for peak torque of the dominant leg knee flexors in concentric muscle action only. A post hoc analysis revealed a statistically significant increase in peak torque from the 1st to the 4th measurement (p<0.001; d=0.692) and from the 2nd to the 4th (p<0.01; d=0.564). The differences in the changes of peak torque of the knee flexors and extensors depending on type of muscle action and tendencies found in the H/Q ratios throughout the annual training cycle indicate that strength assessment of the knee flexors and extensors and their balance throughout the annual training cycle could be beneficial for elite male adolescent soccer players both in terms of performance and risk of injury.
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Purpose: To investigate the effects of combining low-intensity endurance training (LIT) with one high-intensity endurance training (HIT) session every 7-10 days (EXP, n = 7) vs. traditional approach focusing on LIT (TRAD, n = 6) during the transition period. The effects of different training strategies during the transition period were investigated after the transition period and at the beginning of the subsequent competition season. Methods: Well-trained cyclists were tested after the competition season, after an 8-week transition period, and after a 16-week preparatory period, before the subsequent competition season. The only difference between groups was a larger time with HIT during the transition phase in EXP. Results: It was very likely that EXP had a larger impact on power output at 4 mmol L(-1) [la(-)] after both the transition period and after the preparatory period than TRAD [between-group change (90% CI): 10.6% (8.2%) and 12.9% (11.9%), respectively]. It was very likely that EXP had a larger impact on mean power output in the 40-min all-out trial after the transition period than TRAD [between-group change 12.4% (7.6%)]. EXP was also likely to have a larger improvement in the 40-min trial performance from pre-test to after the preparatory period than TRAD [between-group change 6.0% (6.6%)]. Conclusion: The present findings suggest that HIT sessions should be incorporated during the transition phase to avoid reduction in fitness and performance level and thereby increase the likelihood of improved performance from the end of one season to the beginning of the subsequent season.
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PurposeThe aim of this study was to examine the effects of a six-week off-season detraining period on exercise performance, body composition, and on circulating sex steroid levels in soccer players.Methods Fifty-five professional male soccer players, members of two Greek Superleague Teams (Team A, n = 23; Team B, n = 22), participated in the study. The first two weeks of the detraining period the players abstained from any physical activity. The following four weeks, players performed low-intensity (50%-60% of VO2max) aerobic running of 20 to 30 minutes duration three times per week. Exercise performance testing, anthropometry, and blood sampling were performed before and after the six-week experimental period.ResultsOur data showed that in both teams A and B the six-week detraining period resulted in significant reductions in maximal oxygen consumption (60,31±2,52 vs 57,67±2,54; p
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In the present study, we investigated the effect of swimming training and sudden detraining on learning ability and spatial memory capability and on neurogenesis and brain-derived neurotrophic factor (BDNF) expression in the hippocampus of mice. Male ICR mice were randomly assigned into three groups (n= 15 in each group): the control group, the swimming training group, and the detraining group. The mice in the swimming training group were made to swim (6 days/week, 60 min/day) for 8 weeks. The mice in the detraining group were accomplished the same swimming program for 4 weeks and then discontinued exercise for 4 weeks. In the present results, enhanced short-term and spatial learning memories and increased hippocampal neurogenesis and BDNF expression were observed in the mice of the swimming training group. In contrast, decreased short-term and spatial learning memories were observed in the mice of the swimming detraining group compared to the control level. Hippocampal neurogenesis and BDNF expression were also decreased in the mice of the detraining group near to the control level. Here in this study, we suggest that sudden cessation of exercise training might bring decline of the brain functions.
The objective of this study is to describe the practice habits, injury frequency, and attitudes and behaviors concerning shoulder pain in high school-aged competitive swimmers and describe the relationship between attitudes and behaviors. Cross-sectional research design. Local swimming clubs. One hundred two swimmers, aged 13-18 years, at the top training level of their club team were included in the study. Participants were given a survey with questions regarding swimming practice and attitudes and behaviors concerning shoulder pain. Practice habits (yards/week, practice/week, dry-land and weight/week, and months swimming/year) and attitudes and behaviors concerning shoulder pain. Subjects completed an average of 6.89 ± 1.41 swimming practices/wk of 6000 to 7000 yd/practice. The majority of swimmers believe that mild and moderate shoulder pain is normal in swimming and should be tolerated to complete practice, while a majority responded that they swim with shoulder pain. Seventy-three percent of swimmers reported using pain medication to manage their shoulder pain. There was a significant correlation between attitude and behaviors of moderate and severe shoulder pain. Club swimmers have a high frequency of practices, comparable to collegiate and professional swimmers. They believe that shoulder pain is normal and should be tolerated to complete practice. The association between the swimmers' attitudes and behaviors indicates that the interventions that educate the swimmers, coaches, and parents may be effective in changing their attitudes and ultimately their behaviors, decreasing the number of athletes who train with shoulder pain.
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Abstract To determine the effects of preparatory phase training on aerobic parameters, resting heart rate variability (HRV) and 5-km performance of high-level endurance runners and the relationship between the percentage change (% change) of resting HRV with the % change of aerobic parameters and 5-km performance. Six runners were assessed before and after seven weeks of training. The aerobic parameters were determined in an incremental test. The HRV was assessed by a heart rate monitor. Athletes performed a 5-km running test in a track. The analysis revealed 'likely' and 'very likely' improvements for velocity associated with maximal oxygen uptake ([Formula: see text]O2max) (20.0±1.0 km·h(-1) to 21.2±0.6 km·h(-1)) and 5-km performance (18.0±0.4 km·h(-1) to 18.9±0.7 km·h(-1)), respectively, as well as 'likely' decrease in high frequency (41.4±18.5 nu to 30.4±14.3 nu), and increase in low frequency (58.5±18.5 nu to 69.6±14.3 nu) band densities. The variation in the velocity associated with [Formula: see text]O2max showed the highest correlation with 5-km performance (r=0.95). The % change in the square root of the mean sum of the squared differences between R-R intervals and standard deviation 1 were highly correlated with variation in 5-km performance (r=0.69 and 0.66). Changes in the velocity associated with [Formula: see text]O2max and vagally mediated HRV were highly associated with 5-km running performance within the investigated team. These results have important implications because these parameters can be assessed longitudinally to monitor adaptation to training.
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Context A number of comprehensive injury-prevention programs have demonstrated injury risk-reduction effects but have had limited adoption across athletic settings. This may be due to program noncompliance, minimal exercise supervision, lack of exercise progression, and sport specificity. A soccer-specific program described as the F-MARC 11+ was developed by an expert group in association with the Federation Internationale de Football Association (FIFA) Medical Assessment and Research Centre (F-MARC) to require minimal equipment and implementation as part of regular soccer training. The F-MARC 11+ has been shown to reduce injury risk in youth female soccer players but has not been evaluated in an American male collegiate population. Objective To investigate the effects of a soccer-specific warm-up program (F-MARC 11+) on lower extremity injury incidence in male collegiate soccer players. Design Cohort study. Setting One American collegiate soccer team followed for 2 seasons. Patients or Other Participants Forty-one male collegiate athletes aged 18–25 years. Intervention(s) The F-MARC 11+ program is a comprehensive warm-up program targeting muscular strength, body kinesthetic awareness, and neuromuscular control during static and dynamic movements. Training sessions and program progression were monitored by a certified athletic trainer. Main Outcome Measure(s) Lower extremity injury risk and time lost to lower extremity injury. Results The injury rate in the referent season was 8.1 injuries per 1000 exposures with 291 days lost and 2.2 injuries per 1000 exposures and 52 days lost in the intervention season. The intervention season had reductions in the relative risk (RR) of lower extremity injury of 72% (RR = 0.28, 95% confidence interval = 0.09, 0.85) and time lost to lower extremity injury (P < .01). Conclusions This F-MARC 11+ program reduced overall risk and severity of lower extremity injury compared with controls in collegiate-aged male soccer athletes.
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The purpose of this paper is to point out some limits and inconsistencies in the table of nonprotein respiratory quotient that is universally used. This table, developed by Lusk in 1924, was derived from biochemical and physical data that are now outdated. A new table of nonprotein respiratory quotient, consistent with modern chemical and physical data, is proposed. The revised table is based on (a) the average composition of human triacylglycerol stores, (b) energy potential of fatty acids and glucose, and (c) the volumes occupied by one mole of oxygen or carbon dioxide (which are not ideal gases) under STPD conditions.
Cross-training is a widely used approach for structuring a training programme to improve competitive performance in a specific sport by training in a variety of sports. Despite numerous anecdotal reports claiming benefits for cross-training, very few scientific studies have investigated this particular type of training. It appears that some transfer of training effects on maximum oxygen uptake (V̇O2max) exists from one mode to another. The nonspecific training effects seem to be more noticeable when running is performed as a cross-training mode. Swim training, however, may result in minimum transfer of training effects on V̇O2max. Cross-training effects never exceed those induced by the sport-specific training mode. The principles of specificity of training tend to have greater significance, especially for highly trained athletes. For the general population, cross-training may be highly beneficial in terms of overall fitness. Similarly, cross-training may be an appropriate supplement during rehabilitation periods from physical injury and during periods of overtraining or psychological fatigue.
Seven female track athletes, ages 15 to 17, were tested for maximum aerobic capacity during the final month of the track season and again three months after cessation of formal training. Maximum values for oxygen consumption, ventilatory volumes, oxygen pulse, rate of working (keal/kg[middle dot]hr) and the 15 minute oxygen debt had all decreased significantly in the detrained state. There were no differences in maximal heart rates or post-test blood lactate levels. The physiological cost of sub-maximal walking was significantly higher in the detrained state. It was concluded that three months without formal training sessions had reduced the cardiorespiratory fitness of these young track athletes to the levels found in non-athletic girls of the same age. (C)1972The American College of Sports Medicine
The effects of 15 days of detraining and 15 days of retraining were studied in 6 well-trained runners. Detraining resulted in significant decreases in the mean activities of succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) of 24 % and 13 %, respectively, but no significant increases in these enzyme activities occurred with retraining. Maximal oxygen uptake (VO2 max) decreased by 4% with detraining (p < 0.05), and increased by a similar amount with retraining. Performance time in an intense submaximal run decreased by 25% (p < 0.05) with inactivity, but still averaged 9% below the initial level after retraining. Maximal heart rate and peak heart rate during the performance run were higher after detraining by 4 and 9 beats per min, respectively (p < 0.05). With retraining, these heart rate values were decreased by 7 and 9 beats per min (p < 0.05). Blood lactate concentrations after the VO2 max and performance run were approximately 20% lower after detraining and retraining (p < 0.05). Muscle fibre areas for three subjects tended to be larger in biopsy samples taken after detraining and retraining. These data suggest that even short periods of detraining result in significant changes in indices of physiological capacity and function in subjects near their upper limit of adaptation, and that a longer period of retraining is necessary for muscle to re-adapt to its original trained state.
The purpose of this study is to compare the effects of 2 strength training methods on the energy cost of running (Cr). Thirty-five moderately to well-trained male endurance runners were randomly assigned to either a control group (C) or 2 intervention groups. All groups performed the same endurance-training program during an 8-week period. Intervention groups added a weekly strength training session designed to improve neuromuscular qualities. Sessions were matched for volume and intensity using either plyometric training (PT) or purely concentric contractions with added weight (dynamic weight training [DWT]). We found an interaction between time and group (p < 0.05) and an effect of time (p < 0.01) for Cr. Plyometric training induced a larger decrease of Cr (218 +/- 16 to 203 +/- 13 than DWT (207 +/- 15 to 199 +/- 12, whereas it remained unchanged in C. Pre-post changes in Cr were correlated with initial Cr (r = -0.57, p < 0.05). Peak vertical jump height (VJHpeak) increased significantly (p < 0.01) for both experimental groups (DWT = 33.4 +/- 6.2 to 34.9 +/- 6.1 cm, PT = 33.3 +/- 4.0 to 35.3 +/- 3.6 cm) but not for C. All groups showed improvements (p < 0.05) in Perf3000 (C = 711 +/- 107 to 690 +/- 109 seconds, DWT = 755 +/- 87 to 724 +/- 77 seconds, PT = 748 +/- 81 to 712 +/- 76 seconds). Plyometric training were more effective than DWT in improving Cr in moderately to well-trained male endurance runners showing that athletes and coaches should include explosive strength training in their practices with a particular attention on plyometric exercises. Future research is needed to establish the origin of this adaptation.
To examine cardiorespiratory fitness, resting cardiac parameters, and muscle oxygenation changes in soccer players having undergone anterior cruciate ligament reconstruction and to assess the benefits of a one-leg cycling (OLC) aerobic training program performed during the rehabilitation period. Randomized clinical trial. Outpatient clinic, primary care. Twenty-four, male, regional-level soccer players who had undergone surgical reconstruction of the anterior cruciate ligament of the knee. Patients were randomly assigned to 1 of 2 groups: either an individualized OLC aerobic training program with the untreated leg plus a rehabilitation program (training group, TG) or a group that received the same rehabilitation program but without aerobic training (control group, CG). Outcome measurements assessed before (T1) and after 6 weeks (T2) were stroke volume (SV) and end-diastolic volume (EDV) during resting cardiac echography measurement and peak work rate (W(peak)), peak O(2) uptake (VO(2)peak), peak minute ventilation (VE(peak)), first and second ventilatory threshold (VT1 and VT2), leg muscle oxygenation (LMO(2)), and blood volume (LMBV) during maximal graded tests performed with the untreated leg. At T1, there was no significant difference between TG and CG. For TG, W(peak), VE(peak), VT1, VT2, LMO(2), and LMBV at each work rate were significantly higher at T2 than at T1. For CG, W(peak), VO(2)peak, VE(peak), VT2, SV, and EDV decreased significantly at T2 in comparison with T1. One-leg cycling training could involve specific adaptations in comparison to a standard rehabilitation program. Moreover, OLC training during rehabilitation seems to stop the effects of hypoactivity.
This study examined if measures associated with distance running performance were affected by short-term (14 d) training cessation in 12 distance runners. VO2max decreased by approximately 3 (mean +/- SE, 61.6 +/- 2.0 vs 58.7 +/- 1.8, p < 0.05) with training cessation. Time to exhaustion (TTE) during the incremental VO2max test decreased by 1.2 min (13.0 +/- 0.5 vs 11.8 +/- 0.5 min, p < 0.001) and maximal heart rate increased (p < 0.001) by 9 beats per minute (BPM). No changes in running economy (75 and 90% VO2max) were evident, although submaximal heart rate increased by 11 BPM (p < 0.001) at both running speeds. Other evidence for detraining were decreases in estimated resting plasma volume (-5.1 +/- 1.9%) and muscle citrate synthase activity (-25.3 +/- 2.6%, p < 0.05). Muscular atrophy (muscle fiber cross-sectional area) was not evident. TTE and submaximal heart rate exhibited relatively large percent changes (-9 and +6%, respectively) compared to VO2max (-4%). These findings indicate that the reduction in VO2max with short-term training cessation is relatively small. TTE and submaximal heart rate may be easily measured, yet more sensitive indicators of decrements in distance running performance.
The purpose of these papers is to review and discuss the fundamental concepts and problems underlying cardiovascular fitness and spinal cord injury. Particular attention is paid to several modes of exercise available to individuals with spinal cord injury (SCI)--voluntary arm-crank and wheelchair ergometry, electrical stimulation leg cycle ergometry, and combined voluntary arm-cranking and electrical stimulation leg (hybrid) exercise. The effects of level of injury, active muscle mass, and sympathetic dysfunction upon acute central hemodynamic adjustments during exercise testing and chronic training adaptations are discussed for both quadriplegics and paraplegics. Several topics for future research are suggested.