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Post-Season Detraining Effects on Physiological and Performance Parameters in Top-Level Kayakers: Comparison of Two Recovery Strategies
Abstract
This study analyzed changes in physiological parameters, hormonal markers and kayaking performance following 5-wk of reduced training (RT) or complete training cessation (TC). Fourteen top-level male kayakers were randomly assigned to either a TC (n = 7) or RT group (n = 7) at the end of their competitive season (T1). Subjects undertook blood sampling and an incremental test to exhaustion on a kayak ergometer at T1 and again following 5 weeks of RT or TC (T2). Maximal oxygen uptake (VO2max) and oxygen uptake at second ventilatory threshold (VT2) significantly decreased following TC (-10.1% and -8.8%, respectively). Significant decreases were also observed in RT group but to a lesser extent (-4.8% and - 5.7% respectively). Heart rate at VT2 showed significant increases following TC (3.5%). However, no changes, were detected in heart rate at VO2max in any group. Peak blood lactate remained unchanged in both groups at T2. Paddling speed at VO2max declined significantly at T2 in the TC group (-3.3%), while paddling speed at VT2 declined significantly in both groups (-5.0% and -4.2% for TC and RT, respectively). Stroke rate at VO2max and at VT2 increased significantly only following TC by 5.2% and 4.9%, respectively. Paddling power at VO2max and at VT2 decreased significantly in both groups although the values observed following RT were higher than those observed following TC. A significant decline in cortisol levels (-30%) was observed in both groups, while a higher increase in testosterone to cortisol ratio was detected in the RT group. These results indicate that a RT strategy may be more effective than complete TC in order to avoid excessive declines in cardiovascular function and kayaking performance in top-level paddlers.
... When inactivity is prolonged up to 3 weeks, there is a decrease of 4.18% (Martin et al., 1986). After 5 weeks there is a decrease of 10.1% (García-Pallarés et al., 2009), following 56 days a decrease of 13% (Coyle et al., 1984;Coyle et al., 1985) and after 2 months a decrement of 20% (Martin et al., 1986). No further significant decrements are found after 12 weeks (Coyle et al., 1985;Martin et al., 1986). ...
... Conversely, over a more extended period of partial training reduction, a cohort of triathlon athletes, proficient in running and cycling, experienced a decline in endurance capacity (specifically, Time To Exhaustion at 75% VO 2 max), reducing it by 21% when engaging in only one weekly low-volume High-Intensity Interval Training (HIT) session (35 min at 95% HRmax) (Madsen et al., 1993). Short-term detraining has shown an elevation in blood lactate concentration following submaximal exercise (García-Pallarés et al., 2009;Chen et al., 2022). This increase, coupled with altered Mg 2+ transport from the extracellular to the intracellular compartment, potentially inhibits Ca 2+ release from the sarcoplasmic reticulum (Głyk et al., 2022) ...
... While the previously mentioned results primarily focus on assessing the decline resulting from complete detraining involving the total cessation of endurance activity, only a limited number of studies have attempted to examine the impact of a partial reduction in training load (in terms of both volume and intensity) on certain physiological and performance parameters. In short-term training reduction protocols, maintaining VO 2 max levels appears achievable when combining a minimal volume of low-intensity training with at least one weekly moderate-to-high intensity training session (García-Pallarés et al., 2009). Conversely, a minor decline may manifest during short intervals when highintensity training volume is omitted or during extended training transition phases (Almquist et al., 2020). ...
Background: A training program can stimulate physiological, anatomical, and performance adaptations, but these improvements can be partially or entirely reversed due to the cessation of habitual physical activity resulting from illness, injury, or other influencing factors.
Purpose: To investigate the effects of detraining on cardiorespiratory, metabolic, hormonal, muscular adaptations, as well as short-term and long-term performance changes in endurance athletes.
Methods: Eligible studies were sourced from databases and the library up until July 2023. Included studies considered endurance athletes as subjects and reported on detraining duration.
Results: Total cessation of training leads to a decrease in VO2max due to reductions in both blood and plasma volume. Cardiac changes include decreases in left ventricular mass, size, and thickness, along with an increase in heart rate and blood pressure, ultimately resulting in reduced cardiac output and impaired performance. Metabolically, there are declines in lactate threshold and muscle glycogen, increased body weight, altered respiratory exchange ratio, and changes in power parameters. In the short term, there is a decrease in insulin sensitivity, while glucagon, growth hormone, and cortisol levels remain unchanged. Skeletal muscle experiences reductions in arterial-venous oxygen difference and glucose transporter-4. Implementing a partial reduction in training may help mitigate drastic losses in physiological and performance parameters, a consideration when transitioning between training seasons.
Conclusion: There is a dearth of data investigating the detraining effects of training reduction/cessation among endurance athletes. Delving deeper into this topic may be useful for professionals and researchers to identify the optimal strategies to minimize these effects.
... (24) The consequence of this is an increased focus on structure and accountability during unsupervised periods. Other studies have reported detraining effects following reduced exercise load or complete exercise cessation in populations such as older adults(31), kayakers (20), and rugby players. (23) A C C E P T E D 3 The limitation of the currently existing research models is that they lack real-world extrapolation; they maintain structure and/or supervision in a way that is not compatible with collegiate rugby. ...
... Prior research, although limited, has indicated that brief bouts of training cessation in competitive athletic populations may elicit significant losses in physiological capacities. (20,23). A similar outcome has been found when training structure is provided, but the training itself is unsupervised. ...
... A possible explanation is that this break falls at a time during the season in which a small reduction of allostatic load may enhance physical recovery via decreases in cortisol, increases in testosterone, and recovery of adrenal function. (6,20,30,32) ...
This study analyzed the changes in athletic performance and anthropometric characteristics in collegiate male club rugby athletes (n=14) following a four-week winter break. All measurements were collected prior to and after the break. Body composition was assessed by body mass index and hydrostatic weighing. Performance measurements were: VO2 max, vertical jump, 10-yard sprint, squat max, and bench press max. Prior to testing, each subject was acclimated to the protocols to reduce learning effects. During the four-week break, no workouts were provided for the athletes; it was unsupervised and unstructured. Participants were required to maintain and submit self-reported nutritional and activity logs during this period. After the break, the athletes demonstrated a 5.0% improvement in VO2 max (absolute increase of 2.25 ml/kg/min), 6.8% improvement in vertical jump (1.50 inches), and a 14.3% increase in squat max (38.64lb). Although increases in bodyweight (1.0%) were not significant, body fat percentage exhibited a relative increase of 19.3% (absolute change from 13.35% to 15.93%). A significant discriminate function analysis indicated statistical differences between groups based on these variables. Self-report behavior logs confirmed participation in >3 days of moderate to intense physical activity per week, but somewhat poor dietary habits. These results indicate that collegiate rugby athletes may not need prescribed exercise routines during seasonal breaks in the athletic schedule. However, it may be beneficial to provide structured nutritional advice during unsupervised periods.
... Thus, although the available research is not specifically derived from strength athletes, it provides at least some reassurance that muscle strength, quality and mass will not diminish entirely following significant periods without training (Table 2). Further, functional losses may be attenuated with minimal training frequencies, for example see [36], and is discussed further in Section 3.1. Table 2. Brief overview and summary of main findings regarding neuromuscular outcomes from reported studies. ...
... A handful of studies have demonstrated that performing resistance training once or twice per week can minimize the loss of cardiorespiratory function [36] or, more specifically, maintain [37,38] or improve maximum strength [39] in some populations. Specifically, after an 8-week strength training period Tavares et al. [38] reported that half-squat one-repetition maximum strength and quadriceps cross sectional area were maintained when performing either 1 or 2 training sessions per week over a subsequent 8-week detraining period (exercise regime: 3-4 sets of 6-12 RM half-squat and knee extension exercise) when compared to ceasing training entirely. ...
The ongoing global pandemic brought about by Coronavirus II (SARS-Cov-2 or COVID-19) has caused an ongoing cessation of sporting competitions and training facility closures. This is a fundamental challenge for amateur and elite sporting professionals. Although recommendations have been provided for team-sport athletes to maintain general and sport-specific conditioning, these methods are often not optimal for strength athletes (i.e., powerlifting (PL) and weightlifting (WL)) due to the unique and narrow set of performance requirements posed by these sports. The purpose of this review is to provide evidence-based information and recommendations and highlight potential strategies and approaches that may be used by strength (PL and WL) athletes during the current global crisis. Collectively, we provide evidence from resistance training literature regarding the loss of muscle strength, power and mass, minimum training frequencies required to attenuate such losses and training re-adaptation. Additionally, we suggest that time off training and competition caused by ongoing restrictions may be used for other purposes, such as overcoming injury and improving movement quality and/or mobility, goal setting, psychological development and emphasizing strength sports for health. These suggestions are intended to be useful for coaches, strength athletes and organizations where existing training strategies and recommendations are not suitable or no longer feasible.
... T he concept of different exercise training strategies refers to the manipulation of selected training variables, e.g., load, volume, intensity, recovery, and exercise type, to achieve a high-level sports performance by combining different training loads and intensities within the same number of training sessions or cycles (9,23). In this vein, high-intensity interval exercise training (HIIT) seems to be more effective than continuous training (CT) for the improvement of physical condition and sports performance (12,13). ...
... All participants had participated in national kayak championships and had a training experience of 4 years. Before the experimental period, all participants were training 3-4 times per week, using both continuous and interval training methods; however, a detraining period of 6 weeks was applied to all participants before starting the training period (9). (15). ...
Papandreou, A, Philippou, A, Zacharogiannis, E, and Maridaki, M. Physiological adaptations to high-intensity interval and continuous training in kayak athletes. J Strength Cond Res XX(X): 000-000, 2018-High-intensity interval training (HIIT) seems to be more effective than continuous training (CT) for the improvement of physical condition and sports performance. This study compared physiological adaptations with HIIT and CT in flat water kayak athletes. Twenty-four national-class kayakists were divided into 3 groups (n = 8 per group), 2 of which participated in an 8-week CT or HIIT program, whereas the third one served as control (C). An incremental maximum oxygen uptake (V[Combining Dot Above]O2max), a maximal anaerobic Wingate-type, as well as 1,000-m (T1,000 m) and 200-m (T200 m) time test were performed before and after the training period on a kayak ergometer, to determine changes in V[Combining Dot Above]O2max, peak blood lactate ([La]peak), paddling speed at V[Combining Dot Above]O2max (PSVO2max), heart rate at V[Combining Dot Above]O2max (HRpeak), paddling economy speed (PEs; speed at 75% of V[Combining Dot Above]O2max), paddling speed at anaerobic ventilatory threshold (PSVT2), maximal paddling speed (PSpeak), and reduction of PSpeak (PSR). V[Combining Dot Above]O2max, [La]peak, HRpeak, and PSR did not change after the 8-week training compared with baseline in either training group (p > 0.05). However, significant changes were found in PSVT2 and T200 m (HIIT), PSVO2max, PEs, PSpeak, and T1,000 m (CT and HIIT) (p < 0.05-0.0001) as compared to baseline. Moreover, percent changes were different between the training groups in PEs, and between control and training groups in PSpeak and PSVO2peak (p < 0.05-0.01). Both training programs improved physiological and performance variables; however, HIIT resulted in significant changes of PSVT2 and T200 m and higher improvement of PEs with 15 times less training time compared with CT. Thus, HIIT seems more time-efficient than CT for improving paddling economy of kayaking performance.
... period, is common practice in well-trained and elite cyclists (Lucia et al. 2000; Paton and Hopkins 2005; Sassi et al. 2008). However, to our knowledge, no research has investigated the effect of different training strategies during the transition period on performance at the beginning of the subsequent competition period in well-trained cyclists. Garcia-Pallares et al. (2009) compared the effects of a 5-week transition period with either reduced training volume performed at moderate intensity or total absence of training in toplevel kayakers. They found that reduced training reduced the decline in maximal oxygen uptake (VO2max) and power output at second ventilator threshold compared with no training (Garcia ...
... Garcia-Pallares et al. (2009) compared the effects of a 5-week transition period with either reduced training volume performed at moderate intensity or total absence of training in toplevel kayakers. They found that reduced training reduced the decline in maximal oxygen uptake (VO2max) and power output at second ventilator threshold compared with no training (Garcia-Pallares et al. 2009). However, based on the respective ~6% and ~11% decline in VO2max and threshold power, it might be hypothesized that in well-trained athletes, some amounts of high intensity endurance training (HIT) must be incorporated in the recovery period if the aim is to avoid a decline in fitness level. ...
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.
... In addition, we have previously shown that 6-10 days of inactivity are associated with reduced glucose tolerance, insulin action, and GLUT-4 transporter levels (5,36). Others have reported reductions in total aerobic capacity (10,14), deltoid muscle respiratory capacity, and muscle glycogen content compared with levels during peak season training (9). Still others have reported significant increases in body weight (4.8 kg) and body fat (BF; 4.3 kg) after 2 months of detraining (DT) in collegiate female swimmers ( _ VO 2 max, 54.9 6 5.8 mlÁkg 21 Ámin 21 ) (1). ...
... These results agree with those of García-Pallarés et al. who reported a significant 11.3% reduction in maximal aerobic power (15) and a 10.1% decrease in maximal oxygen uptake ( _ VO 2 max) and a significant 3.3% decrease in paddling speed at _ VO 2 max (14) after 5 weeks of training cessation in worldclass kayakers. In general, a significant reduction in _ VO 2 peak is consistent in the literature after a cessation of exercise training for 3-12 weeks (10,14,16,28,35). This consistent decrement in aerobic performance is likely the reason for the decreased TTE in this study as has been reported previously (35). ...
Competitive collegiate swimmers commonly take a month off from swim training after their last major competition. This abrupt cessation of intense physical training has not been well studied and may lead to physiopsychological decline. The purpose of this investigation was to examine the effects of swim detraining (DT) on body composition, aerobic fitness, resting metabolism, mood state, and blood lipids in collegiate swimmers. Eight healthy endurance-trained swimmers (V(O2)peak, 46.7 ± 10.8 ml · kg(-1) · min(-1)) performed 2 identical test days, 1 in the trained (TR) state and 1 in the detrained (~5 weeks) state (DT). Body composition and circumferences, maximal oxygen consumption (V(O2)peak), resting metabolism (RMR), blood lipids, and mood state were measured. After DT, body weight (TR, 68.9 ± 9.7 vs. DT, 69.8 ± 9.8 kg; p = 0.03), fat mass (TR, 14.7 ± 7.6 vs. DT, 16.5 ± 7.4 kg; p = 0.001), and waist circumference (TR, 72.7 ± 3.1 vs. DT, 73.8 ± 3.6 cm; p = 0.03) increased, whereas V(O2)peak (TR, 46.7 ± 10.8 vs. DT, 43.1 ± 10.3 ml · kg(-1) · min(-1); p = 0.02) and RMR (TR, 1.34 ± 0.2 vs. DT, 1.25 ± 0.17 kcal · min(-1); p = 0.008) decreased, and plasma triglycerides showed a trend to increase (p = 0.065). Our data suggest that DT after a competitive collegiate swim season adversely affects body composition, fitness, and metabolism. Athletes and coaches need to be aware of the negative consequences of detraining from swimming, and plan off-season training schedules accordingly to allow for adequate rest/recovery and prevent overuse injuries. It's equally important to mitigate the negative effects on body composition, aerobic fitness and metabolism so performance may continue to improve over the long term.
... These improvements in VO 2peak were likely due to the relatively low initial endurance level exhibited by the athletes as a consequence of the previous 5-week transition period. A decrease in maximal aerobic power after several weeks of training cessation has been reported for endurance athletes (Coyle et al. 1984;García-Pallarés et al. 2009b, 2010Mujika and Padilla 2000). Thus, after resuming formal training, it seems logical that part of the aerobic fitness level was quickly regained, regardless of the training intensities and methods used. ...
... Thus, an increased stroke rate would be needed to maintain the required paddling power output and/or boat speed. These data are in agreement with a recent study that reported similar increases in stroke rate following 5 weeks of training cessation in toplevel kayakers (García-Pallarés et al. 2009b). Therefore, a tapering phase subsequent to a BP cycle may also lead to greater improvements of kayaking performance (i.e. ...
This study was undertaken to compare training-induced changes in selected physiological, body composition and performance variables following two training periodization models: traditional (TP) versus block periodization (BP). Ten world-class kayakers were assessed four times during a training cycle over two consecutive seasons. On each occasion, subjects completed an incremental test to exhaustion on the kayak ergometer to determine peak oxygen uptake (VO(2peak)), VO(2) at second ventilatory threshold (VO(2) VT2), peak blood lactate, paddling speed at VO(2peak) (PS(peak)) and VT2 (PS( VT2)), power output at VO(2peak) (Pw(peak)) and VT2 (Pw( VT2)), stroke rate at VO(2peak) (SR(peak)) and VT2 (SR( VT2)) as well as heart rate at VO(2peak) and VT2. Volume and exercise intensity were quantified for each endurance training session. Both TP and BP cycles resulted in similar gains in VO(2peak) (11 and 8.1%) and VO(2) VT2 (9.8 and 9.4%), even though the TP cycle was 10 weeks and 120 training hours longer than the BP cycle. Following BP paddlers experienced larger gains in PS(peak), Pw(peak) and SR(peak) than those observed with TP. These findings suggest that BP may be more effective than TP for improving the performance of highly trained top-level kayakers. Although both models allowed significant improvements of selected physiological and kayaking performance variables, the BP program achieved similar results with half the endurance training volume used in the TP model. A BP design could be a more useful strategy than TP to maintain the residual training effects as well as to achieve greater improvements in certain variables related to kayaking performance.
... With higher LnRMSSD observed in these swimmers, it is highly likely that they could maintain aerobic capacity during the lockdown, mainly due to an increase in training volume and physical activity. During the lockdown period, despite the inability to engage in swimming training, swimmers were able to maintain their cardiovascular capabilities, which is in line with previous studies [24,25]. Given that our athletes engaged in dry land training during this period, it's plausible that these sessions helped prevent significant declines in cardiovascular function and restore baseline HRV values. ...
... After 2 weeks of detraining, a significant decrease in the surface electromyogram activity of some muscles was observed [29]. An inactivity period leads to increased levels of growth hormone (even more than 50%), testosterone and the testosterone-to-cortisol ratio, with a significant decrease in cortisol [29,30] and enzyme creatine kinase levels. These changes may correspond to an increase in anabolic processes, however, without the effect of muscle hypertrophy due to the lack of training stimulus [29]. ...
An athlete’s training aims to achieve the highest possible sports results by improving physical dispositions which lead to cardiac adaptive changes. The annual training cycle is divided into periods. The preparatory period begins with gradually increasing training intensity and volume until the competitive period occurs, when the athlete’s maximum performance is expected. Finally, the athlete enters a phase of loss of fitness, which is called detraining. Detraining is a time of resting both physically and mentally from the training regime and usually lasts about 4 weeks for endurance athletes. We collected data from much research on athletes’ detraining. According to these data, the earliest change after detraining seems to be a decrease in left ventricular wall thickness and left ventricular mass, followed by decreased performance parameters, diastolic diameter of the left ventricle and size of the left atrium. A reversal of adaptive changes affects the left heart chamber first, then the right atrium and, finally, the right ventricle. Training reduction is often proposed as a method of differentiating an athlete’s heart from cardiomyopathies. The aim of this study is to consider the diagnostic value of detraining in differentiating athletes’ hearts from cardiomyopathies. We suggest that detraining cannot be conclusive in differentiating the disease from adaptive changes. Although a withdrawal of the characteristic morphological, functional and electrocardiographic changes occurs in healthy athletes during detraining, it can also concern individuals with cardiomyopathies due to the lower expression of abnormal features after decreased training loads. Therefore, a quick diagnosis and individual assessments using imaging and genetic tests are essential to recommend a proper type of activity.
... Detraining characteristics may be different depending on the duration of training cessation or insufficient training" (Mujika& Padilla, 2000, p.79). Where short-term detraining is less than 4-6 weeks, while long-term is more than 4-6 weeks (Toraman, 2005;García-Pallarés et al., 2009;Melchiorri et al., 2014). ...
This study aimed to determine the effects of four months of detraining after seven months of soccer training on explosive performance in young amateur soccer players. Nine players (mean±SD: age, 18.33±0.5 years; height, 177.11±5.51 cm; weight, 63.75±8.21) from an Algerian amateur team participated in this study. To determine the effects of detraining, 10-m and 20-m, Zig zag, and countermovement jump tests were used in this study. When comparing measurements before and after the 04 months of detraining, a significant decrease in 10-m (p < 0.01), 20-m (p < 0.05) sprint and zig zag (p < 0.05) tests were observed. There was no statistically significant in the CMJ test, but there is a trend of decrease in it (35.66 ± 4.76 vs 33.77 ± 2.94). Researchers concluded that a four-month detraining reduces the explosive performance of young soccer players. Therefore, players must remain active through carefully suggested training programs if the off-period of the season is prolonged for any reason.
... As there is significant difference, Analysis of covariance (ANCOVA) is used to test the data of adjusted post test mean values of Control group, Kho Kho group and Kabaddi group on Cooper's 12 min Run/Walk. (2,87) at 0.01 level of confidence. Therefore it was found that there is no significant difference of the pre test mean values between the three groups. ...
The purpose of the study was to find out the effect of interval training and detraining on cardio respiratory endurance and breathe holding time among male Kho kho and Basketball players. To achieve the purpose of the study, N=90 male Kho kho and Basketball players from Government Junior college(Boys), Mahabubabad and Government Degree college, Mahabubabad, Telangana were selected randomly as samples from total population and aged between 18-25 years. Further the players were divided into three equal groups as n=30 (Basketball group-BBG), n=30 (Kho kho group-KKG), n=30 (Control group-CG). The experimental design for this study were as follows, a pre and posttest was administrated before and after the 12 weeks of interval training on cardio respiratory endurance and breathe holding time. The CG (Control group) was not given any type of training and they are settled for their daily routine workouts. To know the effect of detraining, the coopers 12 min run/walk and breath holding time tests were administrated on 10 th , 20 th , 30 th , 40 th and 50th days for the data collection after the training period. With appropriate statistical tests the results was analyzed with the help of the software package of social science (SPSS 20.0). It was found that there was a significant difference found in experimental groups and no significant difference in control group. There was a significant decrease in performance after 20 days in detraining period.
... Likewise, the magnitude of detraining following an off-season has been negatively associated with performance progression in the subsequent season in highly trained swimmers (Mujika et al., 1995). Moreover, decreased aerobic (García-Pallarés et al., 2009) and neuromuscular (García-Pallarés et al., 2010) functions were reported in world-class kayakers following a 5week transition period, with greater declines observed in complete training cessation compared to reduced training. Furthermore, divergent decay profiles of neuromuscular functions following resistance training cessation have been documented in elite/sub-elite cyclists with more rapid decreases in explosive power production capacities compared to muscular performance at lower contraction velocities (Bláfoss et al., 2022;Rønnestad et al., 2016). ...
Olympic sailing is a complex sport where sailors are required to predict and interpret weather conditions while facing high physical and physiological demands. While it is essential for sailors to develop physical and physiological capabilities toward major competition, monitoring training status following the competition is equally important to minimize the magnitude of detraining and facilitate retraining. Despite its long history in the modern Olympics, reports on world-class sailors' training status and performance characteristics across different periodization phases are currently lacking. This case study aimed to determine the influence of training cessation and subsequent retraining on performance parameters in a world-class female sailor. A 31-year old female sailor, seventh in the Women's Sailing 470 medal race in Tokyo 2020, completely stopped training for 4 weeks following the Olympics, and resumed low-intensity training for 3 weeks. Over these 7 weeks, 12.7 and 5.3% reductions were observed in 6 s peak cycling power output and jump height, respectively, with a 4.7% decrease in maximal aerobic power output. Seven weeks of training cessation-retraining period induced clear reductions in explosive power production capacities but less prominent decreases in aerobic capacity. The current findings are likely attributed to the sailor's training characteristics during the retraining period.
... In the current study, the home-based moderate to heavy intensity interval training program consisting of aerobic, muscle strength, and stretching exercises was insufficient to preserve V O 2max . Indeed, the average V O 2max reduction was 8.96 ± 2.49%, consistent with that reported in previous studies during Covid-19 restriction [12,16,42] and postseason detraining period [43,44]. It seems that a supervised home-based exercise training program during the Covid-19 restriction was an insufficient stimulus to maintain aerobic capacity in high-level kayak athletes. ...
Purpose
The Covid-19 restriction exposed most athletes to insufficient training stimuli leading to detraining. This study investigated whether a home-based exercise training program could preserve body composition and exercise performance in young high-level kayak athletes during Covid-19 restriction.
Methods
Seventeen healthy young high-level kayak athletes (10 males and 7 females), aged 14.7 ± 1 yrs, participated in this study. A 7-week home-based training program was followed during Covid-19 restriction. Baseline measurements were assessed 4 weeks before Covid-19 pandemic and ended on 4 May 2020. Body composition, flexibility, isometric muscle trunk strength (Biodex), anaerobic power (30-s all-out trial), and aerobic capacity (4-min maximal test) were evaluated. Personal daily loads and wellness details were collected with AthleteMonitoring.com software.
Results
Home-based exercise training program was effective to improve flexibility (9.20 ± 2.85%) and lean body mass (3.96 ± 0.89%), to maintain muscle strength, anaerobic power, body mass, and body fat percentage but insufficient to maintain aerobic capacity (− 8.96 ± 2.49%).
Conclusion
The findings of the present study potentially highlight the importance of the implementation of such a program to minimize the detraining effect on young athletes during periods of movement restriction caused by pandemics.
... The two strategies were found to lead to a reduction in maximal oxygen uptake, but the reduction in reduced training was less than that in training cessation, which is consistent with the findings of our study. This study found that the maximum oxygen uptake in the reduced training group was reduced by~10%, which was less than that in the training cessation group (~18%) [25]. Our results are also consistent with the findings in other exercise model athletes, e.g., in well-trained endurance athletes [26,27], soccer players [28], and team players [29], the maximal oxygen uptake decreased significantly after 2-8 weeks of reduced training. ...
Background:
The global coronavirus disease pandemic (COVID-19) has had a considerable impact on athletic competition and team sports training. Athletes have been forced to train alone at home. However, the isolation training model effects are still unknown.
Purpose:
This study compared the effects of personal isolation training (PIT) and detraining (DT) on specific sport performances (flexibility, power, reaction time, acceleration, and aerobic capacity) and body composition in elite taekwondo athletes.
Methods:
Eleven elite taekwondo athletes were recruited as voluntary subjects. Athletes were randomly paired by weight into the personal isolation training group (PIT group: N = 5, age: 21.2 ± 0.4 years, BMI: 22.2 ± 0.8 kg/m2) or detraining group (DT group: N = 6, age: 19.8 ± 0.3 years, BMI: 23.1 ± 1.0 kg/m2). All subjects performed the same training content prior to the pre-test (T1). When the pre-test was completed, all subjects underwent 12 weeks of PIT or DT. Athletes were then administrated the post-test (T2). The athlete's sport performances and body composition were measured to compare the differences between the two groups (PIT and DT) and two phases (T1 and T2).
Results:
There were no significant differences in kicking reaction time and flexibility in both groups (p > 0.05). The PIT showed significant improvements in 10 m (10M) sprint performance (p < 0.05), and displayed a progress trend in Abalakov jump performance. In addition, the PIT resulted in a better change response in 10M sprint performance (PIT: -4.2%, DT: +2.1%), aerobic endurance performance (PIT: -10.2%, DT: -18.4%), right arm muscle mass (PIT: +2.9%, DT: -3.8%), and trunk muscle mass (PIT: +2.2%, DT: -1.9%) than DT (p < 0.05). The fat mass percentage showed a negative change from T1 to T2 in both groups (p < 0.05).
Conclusions:
PIT showed a trend toward better body composition (arm and trunk muscle) and sport performances (10M sprint and aerobic capacity) compared to DT. This finding may provide information on the effectiveness of a personal isolation training model for optimal preparation for taekwondo athletes and coaches. It may also serve as a useful and safe guideline for training recommendations during the coronavirus disease (COVID-19).
... However, following a gradual increase in training volume and a return to swimming training after the lockdown, a progressive increase in vagal modulation was observed, highlighted by a decrease in resting HR and an increase in Ln rMSSD. It seems that despite the reduced training volume, mostly at the expense of swim-specific training, these swimmers were able to avoid excessive declines in cardiovascular function during the lockdown period, as recently described by Garcia-Pallares et al. [26] The maintenance of landbased aerobic training during the lockdown likely helped to prevent this decline and to restore baseline HR and HRV values. Another key insight from these results is the observation that vagal activity appears to be higher in the last weeks of the study in comparison with the baseline values. ...
Background: Many athletes worldwide have endured home confinement during the COVID-19 pandemic, and their opportunities to train were strongly limited. This study describes the impact of lockdown on training volume and heart rate variability (HRV) in elite swimmers. Methods: HRV data of seven elite males were collected each Monday morning over 20 weeks, including 8 weeks of lockdown. The training volume was quantified retrospectively. Results: During the lockdown period (weeks 4-11) swimming was not allowed, and the total training volume was reduced by 55.2 ± 7.5% compared to the baseline volume (from 27.2 to 12.2 training hours). This drop was associated with a decrease in vagal activity (a 9.2 ± 5.4% increase in resting HR and a 6.5 ± 3.4% decrease in the natural logarithm of rMSSD from baseline values). After the lockdown (weeks 12-20), the training volume was gradually increased before attaining 68.8% and 88.2% of the base-line training volume at weeks 15 and 17, respectively. Resting HR and Ln rMSSD returned to base-line values four weeks after the lockdown. Conclusions: The lockdown period induced a decreased training volume which was associated with a decrease in vagal activity. However, HRV values returned to the baseline 4 weeks after the resumption of swimming training.
... The results of this study regarding the effects of training on performance of participants show that all performance variables have significant differences from preparation phase to competitive phase. These results are consistent with the findings of some other researchers [43,44]. ...
The aim of this study was to evaluate the effect of short-term training on the cardiac structure of Iranian young elite weightlifters. 10 elite male weightlifters from Iran (with an average age of 19.1±3.8 years, weight 104.1±23 kg, height 179.1±4.9 cm) participated in this study as one group. The subjects were tested by one and two-dimensional echocardiography so that their cardiac structure could be determined. From an echocardiographic view, the results showed that there were no significant differences between preparation and competition phases (P>0.05) in terms of the cardiac structure variables. However, athletes' performances showed significant differences in all variables (p < 0.05). It can be concluded that all elite weight lifters were being trained for a long-term-over the years, and all the changes in the echocardiography variables were already made due to the strength of their trainings and a short-term training (from preparation phase to competitive phase) didn't affect the cardiac structure of the weightlifters. It is suggested that in the future, the researchers may use long term training in order to observe changes in the cardiac structure of weightlifters.
... For instance, a large body of literature has focused on understanding strategies used to counteract detraining processes associated with prolonged exposure to microgravity in astronauts (Hargens et al., 2013;Hackney et al., 2015). Some studies have also investigated the effects of reduced training stimuli on physical performance in athletes (Neufer, 1989;Rietjens et al., 2001;García-Pallarés et al., 2009Ormsbee and Arciero, 2012;Joo, 2018). However, these are limited and controversial and they can only provide indirect information on detraining prevention strategies. ...
The COVID-19 pandemic and the forced home confinement have risen a new challenge in the field of sport and exercise sciences, which consists in how to limit and counteract detraining-induced effects among athletes. Despite training cessation has been linked to a multitude of detrimental effects on human health and physical performance, very little is known about how these effects can be prevented. By drawing on discoveries in training reduction and cessation studies, here we illustrate the potential morphological, physiological and functional changes induced by home-confinement. Specific issues associated with the case of injured athletes have also been discussed. This brief report is also expected to provide useful implications for individuals who have to live and face situations of isolation and confinement in extreme environments.
... Pallarés, García, Carrasco, Díaz, Sánchez, Medina (2009) compararon un grupo de Entrenamiento Reducido (ER) y otro de Cese del Entrenamiento (CE), al final del periodo competitivo. Encontraron que el VO2máx y el VT2 (Ventilatory Treshold: Umbral Ventilatorio 2) el Umbral Anaeróbico disminuyó significativamente después de esas 4 semanas de desentrenamiento. ...
Resumen
Objetivo: El objetivo de este trabajo es conocer más profundamente los factores que afectan a los procesos de desadaptación y desentrenamiento del organismo en piragüismo, así como las mejores estrategias para minimizar estos procesos.
Método: Se realizó una fundamentación teórica basándonos en bibliografía científica referente a los factores que condicionan el rendimiento en piragüismo, para conocer este deporte en profundidad, así como la relacionada con el desentrenamiento. A continuación se propusieron 2 grupos experimentales, más 1 control. Cada grupo experimental apoyado por evidencia científica de los posibles beneficios de estrategias mayoritariamente continuas y voluminosas, o por el contrario, más focalizadas en la intensidad e intermitentes.
Resultados: En cuanto a fuerza máxima, el Grupo Experimental 1 y el Grupo Experimental 2 se hallaron más eficaces que el Grupo Control, siendo el Grupo Experimental 2 el mejor en el mantenimiento de esta cualidad en Press Banca y el Grupo Experimental 1 en el Dorsal Banco. Lo mismo ocurría con el tiempo en 1000m, siendo los grupos experimentales los que mejores resultados obtenían, con el Grupo Experimental 2 como el más eficaz en el mantenimiento. En cuanto a la Potencia, la Potencia Máxima es mantenida en mayor grado por el Grupo Experimental 2 tanto en Press Banca como en Dorsal Banco. Ocurre la situación opuesta en la Potencia resistencia, ya que el Grupo Control es el que mayor mantenimiento de la Potencia resistencia obtiene, seguido por el Grupo Experimental 1 y a continuación el Grupo Experimental 2.
Conclusiones: Es necesario pautar el proceso de desentrenamiento, condicionando estas decisiones la forma física con la que se comenzará la temporada subsecuente. Tanto en la Fuerza Máxima en Press Banca como en tiempo en 1000m el Grupo Experimental 2 fue el grupo con mejor mantenimiento, por lo que las estrategias basadas en métodos intermitentes y en la intensidad parecen ser interesantes para estos objetivos. No se obtiene ninguna línea de resultados clara ni consistente sobre qué grupo mantiene mejor la P máx ni la P res.
... Literature on sprint kayaking suggests that impaired neuromuscular performance may reduce an athlete's force-generating capacity in each stroke, resulting in an increase in SR to maintain the same PO. 5,30 Considering that the final T2 effort was completed toward the end of the training session, following bouts Figure 4 -Typical trace of a rolling (10-point) average of an athlete's paddling power output (black) and heart rate (gray) during the aerobic set of the on-water sprint kayak training session. of short, high-intensity (T5) efforts, the higher SRs found here may relate to greater muscular fatigue and as such reduced paddling efficiency. This potential drift in SR throughout training may have implication for the evaluation of training loads, as coaches may overestimate intensity when SR is used as the sole training load measure. ...
Purpose:
To compare methods of monitoring and prescribing on-water exercise intensity (heart rate [HR], stroke rate [SR], and power output [PO]) during sprint kayak training.
Methods:
Twelve well-trained flat-water sprint kayak athletes completed a preliminary on-water 7 × 4-min graded exercise test and a 1000-m time trial to delineate individual training zones for PO, HR, and SR into a 5-zone model (T1-T5). Subsequently, athletes completed 2 repeated trials of an on-water training session, where intensity was prescribed based on individual PO zones. Times quantified for T1-T5 during the training session were then compared between PO, HR, and SR.
Results:
Total time spent in T1 was higher for HR (P < .01) compared with PO. Time spent in T2 was lower for HR (P < .001) and SR (P < .001) compared with PO. Time spent in T3 was not different between PO, SR, and HR (P > .05). Time spent in T4 was higher for HR (P < .001) and SR (P < .001) compared with PO. Time spent in T5 was higher for SR (P = .03) compared with PO. Differences were found between the prescribed and actual time spent in T1-T5 when using PO (P < .001).
Conclusions:
The measures of HR and SR misrepresented time quantified for T1-T5 as prescribed by PO. The stochastic nature of PO during on-water training may explain the discrepancies between prescribed and actual time quantified for power across these zones. For optimized prescription and monitoring of athlete training loads, coaches should consider the discrepancies between different measures of intensity and how they may influence intensity distribution.
... The results of this study regarding the effects of training on performance of participants show that all performance variables have significant differences from preparation phase to competitive phase. These results are consistent with the findings of some other researchers [43,44]. ...
The aim of this study was to evaluate the effect of short-term training on the cardiac structure of Iranian young elite weightlifters. 10 elite male weightlifters from Iran (with an average age of 19.1±3.8 years, weight 104.1±23 kg, height 179.1±4.9 cm) participated in this study as one group. The subjects were tested by one and two-dimensional echocardiography so that their cardiac structure could be determined. From an echocardiographic view, the results showed that there were no significant differences between preparation and competition phases (P>0.05) in terms of the cardiac structure variables. However, athletes' performances showed significant differences in all variables (p < 0.05). It can be concluded that all elite weight lifters were being trained for a long-term-over the years, and all the changes in the echocardiography variables were already made due to the strength of their trainings and a short-term training (from preparation phase to competitive phase) didn't affect the cardiac structure of the weightlifters. It is suggested that in the future, the researchers may use long term training in order to observe changes in the cardiac structure of weightlifters.
... Literature on sprint kayaking suggests that impaired neuromuscular performance may reduce an athlete's force-generating capacity in each stroke, resulting in an increase in SR to maintain the same PO. 5,30 Considering that the final T2 effort was completed toward the end of the training session, following bouts Figure 4 -Typical trace of a rolling (10-point) average of an athlete's paddling power output (black) and heart rate (gray) during the aerobic set of the on-water sprint kayak training session. of short, high-intensity (T5) efforts, the higher SRs found here may relate to greater muscular fatigue and as such reduced paddling efficiency. This potential drift in SR throughout training may have implication for the evaluation of training loads, as coaches may overestimate intensity when SR is used as the sole training load measure. ...
INTRODUCTION:
Current practice for the classification of exercise intensity in Flat-water sprint kayaking involves the use of heart rate (HR) and stroke rate (SR) measures (1). However, HR measures are limited by cardiovascular drift during long-duration bouts and a lag time during high intensity, short-duration efforts (2). Moreover, measures of SR are typically delineated into generic SR-bands which ignore individual variation (1). In other sports, measures of power output (PO) are used for load quantification, since this measure provides the most direct intensity indicator (2). In kayaking, recent advances in wireless instrumented paddle technology now enable coaches to utilise real-time PO measures for training monitoring and prescription. Therefore, the purpose of this study was to compare the use of individualised HR, SR and PO-zones for quantifying sprint kayak training.
METHODS:
Twelve well-trained, sprint kayakers completed a preliminary on-water 7x4 min graded exercise test and a 200, 500 and 1000m time-trial for the delineation of individualised training zones for HR (5-zone model, T1-T5), SR and PO (8-zone model, T1-T8). Subsequently, athletes completed two repeated trials of an aerobic (AER), a high-intensity interval (HIIT) and a sprint interval (SIT) training session, where intensity was prescribed by individual PO-zones. Time spent in T1-T8 during each training session were then compared between PO, HR and SR.
RESULTS:
Compared to PO, time-in-zone using HR was higher in T1 (p<0.001) across all training sessions, was lower for T2 and higher for T4 (p<0.001) in AER, and lower for T5 (p<0.001) in HIIT. Average and peak HR were not different between HIIT and SIT (p=0.823; p>0.999). Time-in-zone using SR was higher for T4 (p<0.001) and T5 (p=0.028) in AER, higher for T4 (p<0.001) and lower for T5 (p=0.005) and T6 (p<0.001) in HIIT, and lower for T7 (p=0.001) and higher for T8 (p=0.004) in SIT compared to PO. In all training sessions, differences were found between the prescribed and actual time spent in T1-T8 when using PO (P<0.001).
CONCLUSION:
HR and SR misrepresented the time spent in T1-T8 as prescribed by PO. HR measures were unable to differentiate the training demands across different high-intensity interval sessions and could therefore misrepresent the training load of such sessions. Measures of SR appear limited for quantifying decrements in intensity due to fatigue, whereas PO may be more suitable. The stochastic nature of PO and the influence of unpredictable on-water conditions likely explain the discrepancies between the prescribed and actual time-in-zone for this measure. For optimised training prescription and monitoring, coaches should consider the discrepancies between different measures of intensity, and how they may influence intensity distribution.
1. N. Bullock et al., Physiological Tests for Elite Athletes 2, 421-433 (2012).
2. D. Sanders et al., International Journal of Sports Physiology and Performance 9, 1-20 (2017).
... While previous studies have shown that driving experience indeed improves one's driving skills, on the opposite, the skills and familiarity with the driving task and onroad situations may degrade over the time if a driver never have the opportunity to drive regularly. Previous studies in the fields of sports have shown that physiological condition and performance of an athlete can be deteriorated due to reduced practice and total rest from practice (Garcia-Pallares et al., 2009;Neufer et al., 1987). Meanwhile, several studies in military field have also shown that there shall be deterioration in skills such as perceptualmotor skills (Ammons et al., 1958;Fleishman & Jr., 1962) as well as cognitive and memory skills (Wisher et al., 1999), if there is no opportunity to practice after obtaining the skills. ...
Driving skills is an accumulation of driving skills learned from training which are further developed through post-licensure on-road driving. A key driving skill is handling interaction with other road users, of which a critical component is mitigating hazards in order to avoid a crash. Driving skills learned through training during licensure degrade over time if the driver never progresses onto on-road driving (i.e. case of inactive driver). Inactive drivers are quite common in Singapore due to high car ownership cost resulting in many people in the population holding a valid driving licence, but yet having limited opportunity to drive. This research investigated the effect of on-road driving experience as well as driving inactivity on driving performance in terms of hazard mitigation. A sample of 91 participants with a range of driving exposure drove on simulated driving environment in the laboratory. Response latency and its constituent components (lag time, time to fixation and perception-response time) in hazards mitigation were used as driving performance indicators. Participants who are active drivers responded faster than inactive (novice and dormant) drivers. Driving training (during licensure) seemed to play only a small role in preparing drivers for hazard mitigation. On-road driving exposure played an important role to strengthen skills in mitigating hazards. Defensive driving course may help drivers to strengthen their driving competencies especially towards responding to hazardous situations.
... Otro de los hándicaps que tiene el entrenamiento en el agua es la necesidad de un mínimo de eficiencia (entendiendo eficiencia como la relación entre el trabajo producido y la energía consumida para ello) para poder llevar a cabo entre- namientos de baja intensidad, tan demandados en los mode- los de distribución de la intensidad que han surgido en los últimos años, combinando entrenamiento de alta intensidad y grandes volúmenes por debajo de umbral aeróbico (Røn- las primeras fases de entrenamiento en el modelo de bloques (García-Pallarés, Carrasco, Díaz & Sánchez-Medina, 2009; García-Pallarés, García-Fernández, Sánchez-Medina &Iz- quierdo- Gabarren, 2010) Los deportistas que practican natación desde edades tem- pranas tienen un mejor desarrollo muscular específico de la modalidad, así como unas capacidades cardiorrespiratorias que son mayores de lo que cabría esperar ver en la jóvenes sin entrenamiento de edades similares (Vaccaro, Clarke& Morris, 1980). Esto permite manifestar más sus capacidades dentro del agua y por lo tanto obtener también un mayor rendimiento. ...
p>La natación tiene unas circunstancias especiales a la hora de entrenar y monitorizar la actividad física que se lleva a cabo. Esto ha hecho que a lo largo del tiempo hayan surgido investigaciones y recursos que nos permitan controlar el proceso de entrenamiento de manera efectiva con alternativas a las variables clásicas. Además, el comportamiento fisiológico en el medio acuático varía respecto al ejercicio físico fuera de él, lo que también hace que sean necesarias algunas adaptaciones metodológicas. Actualmente la natación es un deporte creciente por su gran importancia dentro del triatlón, y las nuevas tecnologías también han logrado ofrecernos nuevas vías para el entendimiento y control del proceso formativo y de entrenamiento. El correcto manejo de las variables que determinan la carga de entrenamiento es la clave para conseguir las adaptaciones que nos aporten una mejora o nos ayude a contrarrestar los factores limitantes del rendimiento. Este trabajo muestra las principales modificaciones que requiere la programación del volumen, intensidad y densidad del entrenamiento en el medio acuático </p
... Several methods of assessing exercise-related physiological stress have been proposed, being the determination of the circulating levels of hormones (i.e., testosterone and cortisol concentrations [13] and the use of psychological questionnaires (e.g., CSAI-2R [14]) the most frequently used. Therefore, serum cortisol concentration has been used as physiological stress marker in individual [15] and team sports (e.g., soccer) [16]. Historically, cortisol concentrations have been determined from blood samples, however, the determination of cortisol in other body fluids, such as saliva, have been recently adopted since it is a non-invasive technique [17], and the results are highly correlated to serum cortisol concentration (r = 0.620, P<0.001; [18]). ...
We sought to measure the response of cortisol concentrations around a professional tennis match and its association with hydration status and neuromuscular performance. Nine professional male tennis players were tested in a rest day, and 2-week after, during the first match of a professional tournament played in a clay-court. Salivary concentrations of cortisol (SalCC) were measured in a resting day (9:00 am and 8:00 pm), at the match day (9:00 am and 8:00 pm) and immediately before and after the match. Hydration status was assessed before the match (urine specific gravity; USG) while fluid turnover was tracked during the match. Finally, counter movement jump (CMJ) and handgrip isometric strength (HS) were measured before and after the match. SalCC, either in the morning (P = 0.161) and afternoon (P = 0.683) was similar in rest and match days. However, SalCC increased after the match (P = 0.033). Participants started the match hypohydrated (USG = 1.026±0.002) and during the match lost 1.0±0.3% of body weight despite 1.035±0.124 L/h of fluid ingested. CMJ and HS did not change post-match (P = 0.210 and P = 0.881, respectively). Correlations between the elevations in SalCC and dehydration (% BW loss) during the match were significant (r = -0.632; P = 0.034). Professional male tennis players did not show an anticipatory increase in SalCC the day of the match and neither signs of neuromuscular fatigue after it. During the match, the mild dehydration (i.e., <1.5%) was associated with the increases in cortisol levels which suggests that dehydration may be an added stress to be considered.
... our data are in agreement with a series of previous studies that reported impairments in aerobic performance and physiological traits of endurance athletes after short-periods of detraining. 11,12,23,24 importantly, in this study, we used magnitude-based inference calculation, whereas the cited studies used traditional parametric analyses. it is probable that the decreases in the 3000 m time-trial performance were associated with the reduction in the Vo 2 max and ventilatory thresholds, which, in turn, are highly correlated with middle-and long-distance endurance performances. ...
Background:
The purpose of this study was to analyze the effects of four weeks of training cessation (TC) on specific endurance performance, resting and post-exercise heart rate variability (HRV) and neuromuscular capacities of high-level endurance runners.
Methods:
Eighteen endurance runners, 8 men and 10 women (25.5 ± 7.5 years; 166.9 ± 7.6 cm; 54.2 ± 6.9 kg), took part in this study. The 3000 m time trial performance, resting HRV, 5'-5' test, squat and countermovement jumps (SJ and CMJ, respectively) and mean propulsive power in the jump squat exercise relative to body mass (MPP JS REL) were performed pre and immediately following the 4-week TC. The inference based on magnitudes were used to analyze the differences between pre and post values.
Results:
The time in the 3000 m time-trial was almost certainly higher after TC. A very likely decrease was noticed in the resting HRV index after the TC period. The differences in all variables analysed during the 5'-5' test were rated as unclear. No differences were observed in SJ and CMJ comparing the pre and post moments of TC, while the MPP JS REL was very likely improved after the TC period.
Conclusion:
The resting HRV accompanied the reductions in the specific endurance performance while the 5'-5' test variables did not. The lack of training stimulus led to improvement in the MPP JS REL, possibly due to the withdrawal of specific endurance training, which strongly concurs with neuromuscular performance.
... One of the elements that affects the symmetry of strength is the training method used in kayaking. The greatest importance is placed on developing the trunk and upper limbs muscles [9]. Canoeists and kayakers are characterized by similar values of the intraclass correlation coefficient for extension at the elbow joint, for flexion at the shoulder joint, and extension at the knee. ...
Study aim: To determine and compare the muscle strength profile and muscle strength symmetry of kayakers and canoeists.
Material and methods: A total of 36 male participants participated in the study, including 25 kayakers and 9 canoeists. Measurements of maximum muscle torque were taken under static conditions for 10 muscle groups: flexors and extensors of the elbow, shoulder, knee, hip, and trunk. Muscle torque was allometrically scaled by body mass. To determine the muscle strength profiles of athletes in both disciplines, residual analysis was used. Two methods were utilized to assess and compare the muscle strength symmetry between left and right limbs. The first one is known as intraclass correlation coefficient (ICC). The second one is an asymmetry coefficient proposed by authors.
Results: The study showed that kayakers obtained lower rates of asymmetry indicators than canoeists in most muscle groups. An overall asymmetry coefficient amounted to 0.77 ± 0.20 and 0.99 ± 0.31 (p < 0.05) for kayakers and canoeists, respectively. Moreover, it was observed that the kayakers and canoeists had similar strength profile. The symmetry assessment of maximum muscle torque corresponds to the characteristics of the studied disciplines.
Conclusions: The intraclass correlation coefficient is recommended as a measure of strength symmetry for muscle groups comparisons. The asymmetry coefficient is recommended for comparison of individuals.
Motor Fitness refers to how an athlete can perform at his or her sport, and involves a mixture of speed, agility, coordination, balance, circulo muscular Endurance, muscular strength Endurance, and reaction time. Detraining is defined as the partial or complete loss of training-induced adaptations in response to cessation of training or a substantial decrease in training load. The purpose of the study was to find out the effect of Plyometric training, Interval training and Detraining on selected Motor Fitness and Physiological variables among male Basketball and Kho Kho players. To achieve the purpose of the study, N=90 male Basketball and Kho Kho players from 322 | P a g e`Government Junior college(Boys), Mahabubabad and Government Degree college, Mahabubabad, Telangana were selected randomly as samples from total population and aged between 18-25 years. Further the players were divided into three equal groups as n=30 (Kho Kho group-KKG), n=30 (Basketball group-BBG), n=30 (Control group-CG). The experimental design for this study were as follows, a pre and post test was administrated before and after the 12 weeks of Plyometric training period on selected Motor Fitness and Physiological variables for the three groups i.e., KKG, BBG and CG respectively. The CG (Control group) was not given any type of training and they are settled for their daily routine workouts only. To know the effect of Detraining, the selected tests were administrated on 10 th , 20 th , 30 th , 40 th and 50th days for the data collection after the training period. Similarly a pre and post test was administrated before and after the 12 weeks of Interval training period on selected Motor Fitness and Physiological variables for the three groups i.e., KKG, BBG and CG respectively. The CG (Control group) was not given any type of training and they are settled for their daily routine workouts only. To know the effect of Detraining, the selected tests were administrated on 10 th , 20 th , 30 th , 40 th and 50 th days for the data collection after the training period. With appropriate statistical tests the results was analyzed with the help of the software package of social science (SPSS 20.0). It was found that with the effect of Plyometric training and Interval training there is a significant difference on selected Motor Fitness and Physiological variables among BBG(Basketball) and KKG(Kho Kho) groups and there was a significant decrease among the groups on selected Motor Fitness and Physiological variables with the effect of Detraining.
V̇O2max, a gold standard for evaluating cardiorespiratory fitness, can be enhanced by training and will gradually decrease when training stops. This study, which followed the Cochrane Collaboration guidelines, is aimed at assessing the effect of short- and long-term detraining on trained individuals’ V̇O2max through a systematic review and meta-analysis and performed a subgroup analysis to evaluate the effects of different ages, detraining formats, and training statuses on V̇O2max variation between short- and long-term training cessation. Web of Science, SPORTDiscus, PubMed, and Scopus, four databases, were searched, from which 21 of 3315 potential studies met the inclusion criteria. Significant decreases in V̇O2max were identified after short-term training cessation (ES=−0.62 [95% CI -0.94; -0.31], p
About the Book: This book compiled with quality research papers of the Two Day International E-Conference on “Trends Issues and Development of Physical Education and Sports” under the theme of “All round development of human personality” jointly organised by Department of Physical Education and Sports Science, Fit India Campaign Committee and Fit India Club, Manipur University, Canchipur in collaboration with National Association of Physical Education and Sports Science (NAPESS). This book has been undertaken by the organisers to share the knowledge of the professionals through their research papers and to exchange their experience and research finding area in the field of physical educational and sports science.
This is the book of the reviews on the concrete solutions to the permanent problems in the physical education and sports science. It is a humble energy to bind the drowning talents of physical education and sports. We express our gratitude, to those humble physical education teachers, research scholars, students, sports lovers, coaches, and sports administrators, who made this chance.
Editor
Dr. L.Santosh Singh
This paper contributes to the debate on anti-doping policies not by evaluating the policy itself but by evaluating the announcement of (new) policy measures. We develop a dynamic model for analyzing the effects of two different types of news shocks: (1) the preannouncement of improved drug testing technological opportunities and (2) the preannouncement of future increases in financial sanctions. We find that the anticipation of policy changes affects the behavior of potentially delinquent athletes. In both scenarios, our simulations show immediately reduced drug abuse among athletes. We conclude that authorities may consider news shocks as an anti-doping strategy.
This study examined the utility of novel measures of power output (PO) compared to traditional measures of heart rate (HR) and stroke rate (SR) for quantifying high-intensity sprint kayak training. Twelve well-trained, male and female sprint kayakers (21.3 ± 6.8 y) completed an on-water graded exercise test (GXT) and a 200-, 500- and 1000-m time-trial for the delineation of individualised training zones (T) for HR (5-zone model, T1-T5), SR and PO (8-zone model, T1-T8). Subsequently, athletes completed two repeat trials of a high-intensity interval (HIIT) and a sprint interval (SIT) training session, where intensity was prescribed using individualised PO-zones. Time-in-zone (minutes) using PO, SR and HR was then compared for both HIIT and SIT. Compared to PO, time-in-zone using HR was higher for T1 in HIIT and SIT (P < 0.001, d ≥ 0.90) and lower for T5 in HIIT (P < 0.001, d = 1.76). Average and peak HR were not different between HIIT (160 ± 9 and 173 ± 11 bpm, respectively) and SIT (157 ± 13 and 174 ± 10 bpm, respectively) (P ≥ 0.274). In HIIT, time-in-zone using SR was higher for T4 (P < 0.001, d = 0.85) and was lower for T5 (P = 0.005, d = 0.43) and T6 (P < 0.001, d = 0.94) compared to PO. In SIT, time-in-zone using SR was lower for T7 (P = 0.001, d = 0.66) and was higher for T8 (P = 0.004, d = 0.70), compared to PO. Heart rate measures were unable to differentiate training demands across different high-intensity sessions, and could therefore misrepresent the training load in such instances. Furthermore, SR may not provide a sensitive measure for detecting changes in intensity due to fatigue, whereas PO may be more suitable.
AIM: The aim of this study was to identify factors that affect sports performance in kayaking.
METHODS: We examined condition- and coordination-related motor skills of 18 male kayakers (mean age: 16.2 years) and determined relationships between these motor skills and sports performance. We also attempted to define the typical level of motor skill fitness of Polish junior kayakers and to compare our findings to results reported by other authors. Following tests and assessments were performed: paddling for 2000 m and 1000 m in a kayak; determining the maximum power achieved during kayak ergometer paddling; determining the maximum oxygen consumption and power achieved during kayak ergometer paddling at an intensity corresponding to the ventilator threshold (VT); determining body composition; running for 1500 m on a track; and measuring the strength, endurance and power achieved during six-repetition series of bench press and bench pull. We also determined the levels of dynamic and static balance of the athletes.
RESULTS: We observed significant relationships between paddling speed and power achieved at VT intensity, the velocity of barbell movement during the bench press and bench pull, and the level of static balance. We also observed a strong correlation between maximum power achieved during kayak ergometer paddling and kayak paddling speed. Accordingly, kayakers should demonstrate a high level of power at VT intensity and maximum power during kayak ergometer paddling. They should also demonstrate a high velocity of barbell movement during the bench press and bench pull, as well as a high level of static balance.
CONCLUSION: On the basis of these results, we determined the typical level of fitness of Polish junior kayakers. The body structures and capabilities of the kayakers we examined did not differ markedly from related data reported by other authors.
Tactical operators are required to carry loads as part of their occupations. Carriage of these loads have been associated with causing physical injuries to the carrier and impairing their ability to perform occupational tasks. One potential means of negating these risks associated with load carriage tasks is through physically conditioning the carrier. Through use of the Frequency, Intensity, Time and Type (F.I.T.T.) formula this review explored the literature to determine the optimal conditioning stimulus to enhance the resilience of tactical operators required to perform load carriage tasks. It was determined that a conditioning stimulus of one load carriage session every 7 to 14 days is required. While the intensity of the load carriage session (load weight, speed of march, terrain grade and type) has the potential to provide a greater training effect than the length of the session (time), both parameters must progress to meet occupational requirements. In general, load carriage-specific training is preferred, with the training effect increased by field exercises that included load carriage tasks. Furthermore, a combined approach of progressive resistance training (especially for the upper body) and aerobic conditioning three times per week is of value. The outcome of this review provides the tactical strength and conditioning coach with an optimal training dose for load carriage conditioning.
International Journal of Exercise Science 5(4) : 354-359, 2012. During the academic year, Army ROTC cadets are required to participate in mandatory physical training; however, during summer months training is not required. The purpose of this study was to determine if there is a change in cadet VO2max after the summer when training is not mandatory. Participants completed a graded exercise treadmill test to determine their VO2max in late spring of 2010 and again in early fall of 2010. Results indicated that over a three-month break from mandatory physical training, a significant decrease in VO2max was seen for both genders in ROTC cadets.
1 Finland HÄKKINEN K., KOMI P.V. & TESCH P.A. Effect of ccmbined concentric ard eccentric strength training and detraining on force-time, muscle fiber-and metabolic characteristics of leg extensor muscles. Scand. J ,Sports Sci. 3 (2): 50-58, 1981. Prog¡essive strength training of combined concentric and eccentric contractions were performed three times a week for 16 weeks by 14 males {20-30 yrs of age) accustomed to weight training. The training peeriod was iollowed bv 8 weeks of detraining. The training program consisted mainly of dynamic exeicises for the ieg-extensovs with loads of 80 to 120 of one maximum repetition The training caused significant improvements in-maximal force (p < 0.001) and various force-time (p (0.05-4.01) para¡àeters. Du¡ing thg I'ast trarning àionìh tbe inãrease in force was gireatly tri¡nited' and there was ¿ decrease in th,e force-time parameters. The marked improvements in mwcle strength were accompanied by ccnsiderable intemål qdaptatioos ,Ín-ttre tnaCned muscle, as Judged from l¡rcreases (p < 0-001) ,iqr. the fibet ãeas ôt tËe Ïast fi¡¡itch (FT) and slow twitch (ST) fibers. Durlng early conditioning improvement i! the qqgs! jump w,as related to tl.e relãtive hypertrop]ty of tr1l ii¡eis fo <0.01). No sier¡j-Êi,cå,r¡t ct¡anges ,in tJre er¡zyme aittv¡tiês oi mÍoki¡¡ase-a¡¡d creatine kirmse were found as a result of-tra¡rrir}g, but i,ndividt¡al charrges in my-o-kinase activity $/ere related to the relative. hypertrop'hy of FT fibers-(p ç 0.05) and Improvernent i+ the squat jump (p < O.Of)-during early conditiontuag. All the ada,p-iatlo:ns'-incilcating musõle hypertrophy occurred. prtm@lv during the last two training mo¡rths. Decreases (p (0.001) in maxirnal force during the detrairring were accompâ-nied bv a sisrificår¡t rediuction in the fi¡b,er areas of ttle fC tp < 0.01) and ST (p < 0.05) tvpes end by a change in bödy-antliropometry.-A periodiè-and partial usage. of àccentr-ic contráctions,-together with conèentric training' is suggested to be effectiùe in training for-maximal force and äso for force-time eharacteristics. In training of longer durations the specific effects of strength trainlng are-obviot¡s and explaiñable by adaptatlons in the trained muscle. Keg tenns: erìzJûne actlvities, muscle mechanics, muscle metabollsn, muscle streng:th.
After 5 months of intense training, eight male swimmers were studied during 4 wk of inactivity. Biopsy specimens from the deltoid muscle revealed that its respiratory capacity (QO2) decreased by 50% (5174 to 2559 microliter X h-1 X g-1) after 1 wk of inactivity. Subsequent weeks of detraining did not change the QO2. Although the trained swimmers' muscle phosphofructokinase and phosphorylase activities were significantly higher (P less than 0.05) than those from a group (N = 8) of untrained men, 4 wk of detraining had no effect on these enzyme activities. Mean (+/-SE) resting muscle glycogen concentrations were significantly higher (P less than 0.05) for the trained swimmers (153 +/- 3 mmol X kg-1) than for the untrained men (85 +/- 7.5 mmol X kg-1). Over the 4 wk of inactivity, the swimmers' muscle glycogen progressively decreased from 153 (+/- 3) to 93 (+/-7) mmol X kg-1. After a standard 183-m swim at 90% of the swimmer's best time for that distance, blood lactate rose from a mean of 4.2 (+/-0.8) at week 0 to 9.7 (+/-0.8) mmol X 1(-1) at week 4. These observations demonstrate dramatic changes in the metabolic characteristics of the swimmer's muscle with a 1-4-wk interruption in training.
The object of this study was to examine changes in muscular strength, power, and resting hormonal concentrations during 6 weeks of detraining (DTR) in recreationally strength-trained men. Each subject was randomly assigned to either a DTR (n = 9) or resistance training (RT; n = 7) group after being matched for strength, body size, and training experience. Muscular strength and power testing, anthropometry, and blood sampling were performed before the experimental period (T1), after 3 weeks (T2), and after the 6-week experimental period (T3). One-repetition maximum (1RM) shoulder and bench press increased in RT at T3 (p </= 0.05), whereas no significant changes were observed in DTR. Peak power output and mean power output significantly decreased (9 and 10%) in DTR at T2. Peak torque of the elbow flexors at 90 degrees did not change in the RT group but did significantly decrease by 11.9% at T3 compared with T1 in the DTR group. Vertical jump height increased in RT at T2 but did not change in DTR. Neither group displayed any changes in 1RM squat, body mass, percent body fat, or resting concentrations of growth hormone, follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, testosterone, cortisol, or adrenocorticotropin. These data demonstrate that 6 weeks of resistance DTR in recreationally trained men affects power more than it does strength without any accompanying changes in resting hormonal concentrations. For the recreational weight trainer, losses in strength over 6 weeks are less of a concern compared with anaerobic power and upper arm isometric force production. Anaerobic power exercise with a high metabolic component coming from glycolysis might be of importance for reducing the impact of DTR on Wingate power performances. A minimal maintenance training program is recommended for the recreational lifter to offset any reductions in performance.
The aim of the present study was to investigate the relationship between physical fitness, heart rate variability (HRV) and cognitive function in 37 male sailors from the Royal Norwegian Navy. All subjects participated in an 8-week training program, after which the subjects completed the initial cognitive testing (pretest). The subjects were assigned into a detrained group (DG) and a trained group (TG) based on their application for further duty. The DG withdrew from the training program for 4 weeks after which all subjects then completed the cognitive testing again (post-test). Physical fitness, measured as maximum oxygen consumption (VO2(max)), resting HRV, and cognitive function, measured using a continuous performance task (CPT) and a working memory test (WMT), were recorded during the pre-test and the post-test, and the data presented as the means and standard deviations. The results showed no between-group differences in VO2(max) or HRV at the pre-test. The DG showed a significant decrease in VO2(max) from the pre- to the post-test and a lower resting HRV than the TG on the post-test. Whereas there were no between-group differences on the CPT or WMT at the pre-test, the TG had faster reaction times and more true positive responses on tests of executive function at the post-test compared to the pre-test. The DG showed faster reaction times on non-executive tasks at the post-test compared to the pre-test. The results are discussed within a neurovisceral integration framework linking parasympathetic outflow to the heart to prefrontal neural functions.
Resistance exercise has been shown to elicit a significant acute hormonal response. It appears that this acute response is more critical to tissue growth and remodelling than chronic changes in resting hormonal concentrations, as many studies have not shown a significant change during resistance training despite increases in muscle strength and hypertrophy. Anabolic hormones such as testosterone and the superfamily of growth hormones (GH) have been shown to be elevated during 15-30 minutes of post-resistance exercise providing an adequate stimulus is present. Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals. Other anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1) are critical to skeletal muscle growth. Insulin is regulated by blood glucose and amino acid levels. However, circulating IGF-1 elevations have been reported following resistance exercise presumably in response to GH-stimulated hepatic secretion. Recent evidence indicates that muscle isoforms of IGF-1 may play a substantial role in tissue remodelling via up-regulation by mechanical signalling (i.e. increased gene expression resulting from stretch and tension to the muscle cytoskeleton leading to greater protein synthesis rates). Acute elevations in catecholamines are critical to optimal force production and energy liberation during resistance exercise. More recent research has shown the importance of acute hormonal elevations and mechanical stimuli for subsequent up- and down-regulation of cytoplasmic steroid receptors needed to mediate the hormonal effects. Other factors such as nutrition, overtraining, detraining and circadian patterns of hormone secretion are critical to examining the hormonal responses and adaptations to resistance training.
A heavyweight male rower, and current Olympic champion, undertook a laboratory-based incremental rowing test on four separate occasions; eight weeks prior to the Sydney Olympics (Pre OG), after eight weeks of inactivity (Post-IA), after 8 weeks of retraining (Post 8) and after a further 12 weeks of training (Post 20). Following the period of inactivity, peak oxygen uptake (VO2peak) declined by 8%, power at reference blood lactate concentrations declined by approximately 100 W (25%), and power at VO2peak was 20% lower. With eight weeks of retraining, rapid improvements were seen. For most parameters, however, the rate of improvement slowed and after 20 weeks of retraining the individual was approaching pre-Olympic levels. VO2 at lactate threshold as a percentage of VO2peak remained unchanged. These results show that detraining in the elite athlete can be pronounced, with rapid improvements upon retraining which slow, so that retraining takes considerably longer to achieve than detraining did. Complete cessation of training should be limited to short periods only in the preparation of the elite heavyweight rower. Any break should, if possible, include 'maintenance training'. In this way any decrements in those physiological parameters associated with 2000 m rowing performance will be minimised.
In order to study the effect of a competitive triathlon season on maximal oxygen uptake (VO2max), aerobic power (AeP) and anaerobic performance (AnP) of the lower limbs, eight triathletes performed exercise tests after: (1) a pre-competition period (Pre-COMP) (2) a competitive period (COMP), and (3) a low (volume and intensity) training period (Post-COMP). The tests were a vertical jump-and-reach test and an incremental exercise test on a cycle ergometer. Ventilatory data were collected every minute during the incremental test with an automated breath-by-breath system and the heart-rate was monitored using a telemetric system.
No changes in VO2max were observed, whereas AeP decreased after Post-COMP compared to Pre-COMP and COMP and AnP decreased during COMP compared to Pre-COMP and Post-COMP. In addition, second ventilatory threshold (VT2) and power output at first ventilatory threshold (VT1) and VT2 decreased after Post-COMP.
This study showed that six weeks of low volume and intensity of training is too long a period to preserve adaptations to training, although a stable maximal oxygen uptake throughout the triathlon season was observed. Moreover, the AnP decrease during COMP was probably in relation with the repetitive nature of the training mode and/or triathlon competitions.
To examine the effect of 6-week of high-intensity interval training (HIT) and of 6-week of detraining on the VO2/Work Rate (WR) relationship and on the slow component of VO2, nine young male adults performed on cycle ergometer, before, after training and after detraining, an incremental exercise (IE), and a 6-min constant work rate exercise (CWRE) above the first ventilatory threshold (VT1). For each IE, the slope and the intercept of the VO2/WR relationship were calculated with linear regression using data before VT1. The difference between VO2max measured and VO2max expected using the pre-VT1 slope was calculated (extra VO2). The difference between VO2 at 6th min and VO2 at 3rd min during CWRE (DeltaVO2(6'-3')) was also determined. HIT induced significant improvement of most of the aerobic fitness parameters while most of these parameters returned to their pre-training level after detraining. Extra VO2 during IE was reduced after training (130 +/- 100 vs. -29 +/- 175 ml min(-1), P = 0.04) and was not altered after detraining compared to post-training. DeltaVO2(6'-3') during CWRE was unchanged by training and by detraining. We found a significant correlation (r2 = 0.575, P = 0.02) between extra VO2 and DeltaVO2(6'-3') before training. These results show that an alteration of extra VO2 can occur without any change in the VO2 slow component, suggesting a possible dissociation of the two phenomena. Moreover, the fact that extra VO2 did not change after detraining could indicate that this improvement may remain after the loss of other adaptations.
Seven endurance exercise-trained subjects were studied 12, 21, 56, and 84 days after cessation of training. Maximal O2 uptake (VO2 max) declined 7% (P less than 0.05) during the first 21 days of inactivity and stabilized after 56 days at a level 16% (P less than 0.05) below the initial trained value. After 84 days of detraining the experimental subjects still had a higher VO2 max than did eight sedentary control subjects who had never trained (50.8 vs. 43.3 ml X kg-1 X min-1), due primarily to a larger arterial-mixed venous O2 (a-vO2) difference. Stroke volume (SV) during exercise was high initially and declined during the early detraining period to a level not different from control. Skeletal muscle capillarization did not decline with inactivity and remained 50% above (P less than 0.05) sedentary control. Citrate synthase and succinate dehydrogenase activities in muscle declined with a half-time of 12 days and stabilized at levels 50% above sedentary control (P less than 0.05). The initial decline in VO2 max was related to a reduced SV and the later decline to a reduced a-vO2 difference. Muscle capillarization and oxidative enzyme activity remained above sedentary levels and this may help explain why a-vO2 difference and VO2 max after 84 days of detraining were still higher than in untrained subjects.
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.
This study was undertaken to analyze changes in selected cardiovascular and neuromuscular variables in a group of elite kayakers across a 12-week periodized cycle of combined strength and endurance training. Eleven world-class level paddlers underwent a battery of tests and were assessed four times during the training cycle (T0, T1, T2, and T3). On each occasion subjects completed an incremental test to exhaustion on the kayak-ergometer to determine maximal oxygen uptake (VO2max), second ventilatory threshold (VT2), peak blood lactate, paddling speed at VO2max (PSmax) and at VT2 (PSVT2), stroke rate at VO2max and at VT2, heart rate at VO2max and at VT2. One-repetition maximum (1RM) and mean velocity with 45% 1RM load (V
45%) were assessed in the bench press (BP) and prone bench pull (PBP) exercises. Anthropometric measurements (skinfold thicknesses and muscle girths) were also obtained. Training volume and exercise intensity were quantified for each of three training phases (P1, P2, and P3). Significant improvements in VO2max (9.5%), VO2 at VT2 (9.4%), PSmax (6.2%), PSVT2 (4.4%), 1RM in BP (4.2%) and PBP (5.3%), V
45% in BP (14.4%) and PBP (10.0%) were observed from T0 to T3. A 12-week periodized strength and endurance program with special emphasis on prioritizing the sequential development of specific physical fitness components in each training phase (i.e. muscle hypertrophy and VT2 in P1, and maximal strength and aerobic power in P2) seems effective for improving both cardiovascular and neuromuscular markers of highly trained top-level athletes.
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 ml.kg-1.min-1 (mean +/- SE, 61.6 +/- 2.0 vs 58.7 +/- 1.8 ml.kg-1.min-1, 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.
In previously sedentary individuals, regularly performed aerobic exercise results in significant improvements in exercise capacity. The development of peak exercise performance, as typified by competitive endurance athletes, is dependent upon several months to years of aerobic training. The physiological adaptations associated with these improvements in both maximal exercise performance, as reflected by increases in maximal oxygen uptake (V̇O2max), and submaximal exercise endurance include increases in both cardiovascular function and skeletal muscle oxidative capacity.
Despite prolonged periods of aerobic training, reductions in maximal and submaximal exercise performance occur within weeks after the cessation of training. These losses in exercise performance coincide with declines in cardiovascular function and muscle metabolic potential. Significant reductions in V̇O2max have been reported to occur within 2 to 4 weeks of detraining. This initial rapid decline in V̇O2max is likely related to a corresponding fall in maximal cardiac output which, in turn, appears to be mediated by a reduced stroke volume with little or no change in maximal heart rate. A loss in blood volume appears to, at least partially, account for the decline in stroke volume and V̇O2max during the initial weeks of detraining, although changes in cardiac hypertrophy, total haemoglobin content, skeletal muscle capillarisation and temperature regulation have been suggested as possible mediating factors. When detraining continues beyond 2 to 4 weeks, further declines in V̇O2max appear to be a function of corresponding reductions in maximal arterial-venous (mixed) oxygen difference. Whether reductions in oxygen delivery to and/or extraction by working muscle regulates this progressive decline is not readily apparent. Changes in maximal oxygen delivery may result from decreases in total haemoglobin content and/or maximal muscle blood flow and vascular conductance. The declines in skeletal muscle oxidative enzyme activity observed with detraining are not causally linked to changes in V̇O2max but appear to be functionally related to the accelerated carbohydrate oxidation and lactate production observed during exercise at a given intensity. Alternatively, reductions in submaximal exercise performance may be related to changes in the mean transit time of blood flow through the active muscle and/or the thermore-gulatory response (i.e. degree of thermal strain) to exercise.
In contrast to the responses observed with detraining, currently available research indicates that the adaptations to aerobic training may be retained for at least several months when training is maintained at a reduced level. Reductions of one- to two-thirds in training frequency and/or duration do not significantly alter V̇O2max or submaximal endurance time provided the intensity of each exercise session is maintained. Conversely, a decrease of one- to two-thirds in exercise training intensity, despite a maintenance of training frequency and duration, reduces both V̇O2max and submaximal endurance time. Thus, it appears that exercise intensity is the principal component necessary to maintain a training-induced increase in V̇O2max and submaximal exercise endurance during periods of reduced training. It is suggested that the maintenance of V̇O2max with reduced training frequency and/or duration may be related to a retention of blood volume. When exercise training intensity is reduced, however, it is possible that the stimulus mediating the relative hypervolaemia observed with aerobic training may be attenuated, thereby accounting for the corresponding decrease in V̇O2max. However, the interactions of possible changes in cardiac hypertrophy and contractility, thermoregulatory strain, total haemoglobin content, capillary density, mean transit time, and skeletal muscle oxidative capacity in relation to changes in V̇O2max and submaximal endurance time with reduced training and detraining warrant further study.
The adaptability of human skeletal muscle to increased (training) and decreased (detraining) usage was studied in 11 athletes over a 42-month-long observation period. Biopsies were taken from the deltoid and the quadriceps muscle, together with measurements of maximum torque output during voluntary knee extensions at high relative to slow speeds of movement. A 16% and 14% decrease in the proportion of type I fibers was seen in the proximal arm and leg muscles, respectively, in the detraining subjects. This conformed with the changes in muscle function. On the other hand, in the training subjects, who increased their activity level through systematic daily physical training over an almost 4-year-long period, there were no significant changes seen in fiber type proportions of either arm or leg muscles. This was presumably due to the smaller net change in physical activity level caused by training as compared to detraining in the subjects of this study. Thus, the results show that fiber type proportions in intact human skeletal muscle are not exclusively determined by heredity, but may also be influenced by environmental factors, such as physical activity level.
To determine the role of preload in maintaining the enhanced stroke volume of upright exercise-trained endurance athletes after deconditioning, six highly trained subjects undergoing upright and supine bicycle ergometry were characterized before and after 3, 8 and 12 weeks of inactivity that reduced oxygen uptake by 20%. During exercise, oxygen uptake, cardiac output by carbon dioxide rebreathing, cardiac dimensions by M-mode echocardiography, indirect arterial blood pressure and heart rate were studied simultaneously. Two months of inactivity resulted in a reduction in stroke volume, calculated as cardiac output/heart rate, during upright exercise (p less than 0.005) without a significant change during supine exercise. A concomitant decrease in the left ventricular end-diastolic dimension from the trained to the deconditioned state was observed in the upright posture (5.1 +/- 0.3 versus 4.6 +/- 0.3 cm; p = 0.02) but not with recumbency (5.4 +/- 0.2 versus 5.1 +/- 0.3 cm; p = NS). There was a strong correlation between left ventricular end-diastolic dimension and stroke volume (r greater than 0.80) in all subjects. No significant changes in percent fractional shortening or left ventricular end-systolic dimension occurred in either position after cessation of training. Estimated left ventricular mass was 20% lower after 3 and 8 weeks of inactivity than when the subjects were conditioned (p less than 0.05 for both). Thus, the endurance-trained state for upright exercise is associated with a greater stroke volume during upright exercise because of augmented preload. Despite many years of intense training, inactivity for only a few weeks results in loss of this adaptation in conjunction with regression of left ventricular hypertrophy.
Following 5 months of competitive training (approximately 9,000 yards.d-1, 6 d.wk-1), three groups of eight male swimmers performed 4 wk of either reduced training (3,000 yard.session-1) or inactivity. Two groups reduced their training to either 3 sessions.wk-1 (RT3) or 1 session.wk-1 (RT1), whereas the third group (IA) did no training. Measurement of muscular strength (biokinetic swim bench) showed no decrement in any group over the 4 wk. In contrast, swim power (tethered swim) was significantly decreased (P less than 0.05) in all groups, reaching a mean change of -13.6% by week 4. Blood lactate measured after a standard 200-yard (183 m) front crawl swim increased by 1.8, 3.5, and 5.5 mM over the 4 wk in groups RT3, RT1 and IA, respectively. In group RT1, stroke rate measured during the 200-yard swim significantly increased (P less than 0.05) from 0.54 +/- 0.03 to 0.59 +/- 0.03 strokes.-1 while stroke distance significantly decreased (P less than 0.05) from 2.50 +/- 0.08 to 2.29 +/- 0.13 m.stroke-1 during the 4-wk period. Both stroke rate and stroke distance were maintained in group RT3 over the 4 wk of reduced training. Group IA was not tested for stroke mechanics. Whereas maximal oxygen uptake decreases significantly (P less than 0.05) over the 4 wk in group RT1 (4.75 to 4.62 l.min-1), no change in maximal oxygen uptake was observed in group RT3. These results suggest that aerobic capacity is maintained over 4 wk of moderately reduced training (3 sessions.wk-1) in well-trained swimmers. Muscular strength was not diminished over 4 wk of reduced training or inactivity, but the ability to generate power during swimming was significantly reduced in all groups.
Human subjects participated in a training/detraining paradigm which consisted of 7 wk of intense endurance training followed by 3 wk of inactivity. In previously sedentary subjects, training produced a 23.9 +/- 7.2% increase in maximal aerobic power (V02max) (group S). Detraining did not affect group S V02max. In previously trained subjects (group T), the training/detraining paradigm did not affect V02max. In group S, training produced an increase in vastus lateralis muscle citrate synthase (CS) activities (nmol.mg protein-1. min-1) from 67.1 +/- 14.5 to 106.9 +/- 22.0. Detraining produced a decrease in CS activity to 80 +/- 14.6. In group T, pretraining CS activity (139.5 +/- 14.9) did not change in response to training. Detraining, however, produced a decrease in CS activity (121.5 +/- 7.8 to 66.8 +/- 5.9). Group S respiratory exchange ratios obtained during submaximal exercise at 60% V02max (R60) decreased in response to training (1.00 +/- 0.02 to 0.87 +/- 0.02) and increased (0.96 +/- 0.02) after detraining. Group T R60 (0.91 +/- 0.01) was not affected by training but increased (0.89 +/- 0.02 to 0.95 +/- 0.02) after detraining. R60 was correlated to changes in CS activity but was unrelated to changes in V02max. These data support the hypothesis that the mitochondrial content of working skeletal muscle is an important determinant of substrate utilization during submaximal exercise.
We measured maximum oxygen uptake, estimated changes in plasma volume, and the cardiac dimensions of 15 male competitive distance runners (28.2 +/- 5.6 yr of age, mean +/- SD) before and after 10 days of exercise cessation. Subjects were habitually active but adjusted their training to run 16 km daily for 2 wk before the study. Subjects were maintained on defined diets for the week before and during the detraining period. Average body weight decreased 1.0 +/- 0.5 kg (P less than 0.001) within 2 days of exercise cessation and was accompanied by a 5.0 +/- 5.9% (P less than 0.01) decrease in estimated plasma volume. No additional changes in body weight and plasma volume occurred during the study, and estimated percent body fat did not change. Resting heart rate, blood pressure, and cardiac dimensions were also unchanged with physical inactivity. In addition, maximum oxygen uptake was not altered although peak exercise heart rate was an average of 9 +/- 5 beats X min-1 (P less than 0.01) or 5% higher after detraining. We conclude that short periods of exercise cessation decrease estimated plasma volume and increase the maximum exercise heart rate of endurance athletes but do not alter their cardiac dimensions or maximum oxygen uptake.
In this study we determined whether the decline in exercise stroke volume (SV) observed when endurance-trained men stop training for a few weeks is associated with a reduced blood volume. Additionally, we determined the extent to which cardiovascular function could be restored in detrained individuals by expanding blood volume to a similar level as when trained. Maximal O2 uptake (VO2max) was determined, and cardiac output (CO2 rebreathing) was measured during upright cycling at 50-60% VO2max in eight endurance-trained men before and after 2-4 wk of inactivity. Detraining produced a 9% decline in blood volume (5,177 to 4,692 ml; P less than 0.01) during upright exercise, due primarily to a 12% lowering (P less than 0.01) of plasma volume (PV; Evans blue dye technique). SV was reduced by 12% (P less than 0.05) and VO2max declined 6% (P less than 0.01), whereas heart rate (HR) and total peripheral resistance (TPR) during submaximal exercise were increased 11% (P less than 0.01) and 8% (P less than 0.05), respectively. When blood volume was expanded to a similar absolute level in the trained and detrained state (approximately 5,500 +/- 200 ml) by infusing a 6% dextran solution in saline, the effects of detraining on cardiovascular response were reversed. SV and VO2max were increased (P less than 0.05) by PV expansion in the detrained state to within 2-4% of trained values. Additionally, HR and TPR during submaximal exercise were lowered to near trained values. These findings indicate that the decline in cardiovascular function following a few weeks of detraining is largely due to a reduction in blood volume, which appears to limit ventricular filling during upright exercise.
Eleven male subjects (20-32 years) accustomed to strength training went through progressive, high-load strength training for 24 weeks with intensities ranging variably between 70 and 120% during each month. This training was also followed by a 12-week detraining period. An increase of 26.8% (P less than 0.001) in maximal isometric strength took place during the training. The increase in strength correlated (P less than 0.05) with significant (P less than 0.05-0.01) increases in the neural activation (IEMG) of the leg extensor muscles during the most intensive training months. During the lower-intensity training, maximum IEMG decreased (P less than 0.05). Enlargements of muscle-fibre areas, especially of fast-twitch type (P less than 0.001), took place during the first 12 weeks of training. No hypertrophic changes were noted during the latter half of training. After initial improvements (P less than 0.05) no changes or even slight worsening were noted in selected force-time parameters during later strength training. During detraining a great (P less than 0.01) decrease in maximal strength was correlated (P less than 0.05) with the decrease (P less than 0.05) in the maximum IEMGs of the leg extensors. This period resulted also in decreases (P less than 0.05) of the mean muscle-fibre areas of both fibre types. It was concluded that improvement in strength may be accounted for by neural factors during the course of very intensive strength training. Selective training-induced hypertrophy also contributed to strength development but muscle hypertrophy may have some limitations during long-lasting strength training, especially in highly trained subjects.
Thirteen subjects participated in an exercise program of bicycling and running 40 min/day, 6 days/wk. After 10 wk they continued to train either 26 of 13 min/day for an additional 15 wk. Intensity and frequency for the additional 15 wk remained the same as the last 3 wk of training. This study was undertaken to gain further insights into whether the increases in maximum uptake (VO2 max), endurance, and cardiac size can be maintained with reduced training durations. The average increases in VO2 max in response to 10 wk training were between 10 and 20% during the bicycle and treadmill testing. After reduced training, VO2 max continued to remain at the training levels in both groups. Short-term endurance (approx 5 min) was also maintained by both groups. Long-term endurance (2 h or more) remained the same in the 26-min group but decreased significantly (10%, 139-123 min) in the 13-min group. Calculated left ventricular mass increased 15-20% after training and remained elevated after reduced training in both groups. We conclude that it is possible to maintain almost all of the performance increases with up to a two-thirds reduction of training duration. Nevertheless, the data provide initial evidence that all aspects of the endurance-trained state may not be regulated uniformly in reduced training, particularly since VO2 max and short-term endurance were maintained, but long-term endurance decreased in the 13-min group.
Seven endurance exercise-trained subjects were studied 12, 21, 56, and 84 days after cessation of training. Maximal O2 uptake (VO2 max) declined 7% (P less than 0.05) during the first 21 days of inactivity and stabilized after 56 days at a level 16% (P less than 0.05) below the initial trained value. After 84 days of detraining the experimental subjects still had a higher VO2 max than did eight sedentary control subjects who had never trained (50.8 vs. 43.3 ml X kg-1 X min-1), due primarily to a larger arterial-mixed venous O2 (a-vO2) difference. Stroke volume (SV) during exercise was high initially and declined during the early detraining period to a level not different from control. Skeletal muscle capillarization did not decline with inactivity and remained 50% above (P less than 0.05) sedentary control. Citrate synthase and succinate dehydrogenase activities in muscle declined with a half-time of 12 days and stabilized at levels 50% above sedentary control (P less than 0.05). The initial decline in VO2 max was related to a reduced SV and the later decline to a reduced a-vO2 difference. Muscle capillarization and oxidative enzyme activity remained above sedentary levels and this may help explain why a-vO2 difference and VO2 max after 84 days of detraining were still higher than in untrained subjects.
The effects of 4 wk of detraining on maximal O2 uptake (VO2max) and on endurance capacity defined as the maximal time to exhaustion at 75% of VO2max were studied in nine well-trained endurance athletes. Detraining consisted of one short 35-min high-intensity bout per week as opposed to the normal 6-10 h/wk. Detraining had no effect on VO2max (4.57 +/- 0.10 vs. 4.54 +/- 0.08 l/min), but endurance capacity decreased by 21% from 79 +/- 4 to 62 +/- 4 min (P < 0.001). Endurance exercise respiratory exchange ratio was higher in the detrained than in the trained state (0.91 +/- 0.01 vs. 0.89 +/- 0.01; P < 0.01). Muscle [K+] values were unchanged during exercise and were similar in the trained and detrained states. Muscle [Mg2+] values were similar at rest and at minute 40 (30.3 +/- 0.9 vs. 30.8 +/- 0.6 mmol/kg dry wt) but increased significantly at exhaustion to 33.8 +/- 1.0 mmol/kg dry wt in the trained state and to 33.9 +/- 0.9 mmol/kg dry wt in the detrained state. The elevated muscle [Mg2+] at exhaustion could contribute to fatigue in prolonged exercise through an inhibition of Ca2+ release from sarcoplasmic reticulum. It is concluded that the endurance capacity can vary considerably during detraining without changes in VO2max. Altered substrate utilization or changes in electrolyte regulation may account for the reduced endurance capacity.
We investigated the effects of 14 d of resistive exercise detraining on 12 power athletes. In comparing performances pre- to post-detraining, there were no significant (P > 0.05) changes in free weight bench press (-1.7%), parallel squat (-0.9%), isometric (-7%) and isokinetic concentric knee extension force (-2.3%), and vertical jumping (1.2%). In contrast, isokinetic eccentric knee extension force decreased in every subject (-12%, P < 0.05). Post-detraining, the changes in surface EMG activity of the vastus lateralis during isometric, and isokinetic eccentric and concentric knee extension were -8.4%, -10.1%, and -12.7%, respectively (all P > 0.05). No significant changes occurred in knee flexion forces or EMGs (P > 0.05). Percentages of muscle fiber types and the Type I fiber area remained unchanged, but Type II fiber area decreased significantly by -6.4% (P < 0.05). Levels of plasma growth hormone (58.3%), testosterone (19.2%), and the testosterone to cortisol ratio (67.6%) increased, whereas plasma cortisol (-21.5%) and creatine kinase enzyme levels (-82.3%) decreased (all P < 0.05). Short-term resistive exercise detraining may thus specifically affect eccentric strength or the size of the Type II muscle fibers, leaving other aspects of neuromuscular performance uninfluenced. Changes in the hormonal milieu during detraining may be conducive to an enhanced anabolic process, but such changes may not materialize at the tissue level in the absence of the overload training stimulus.
Detraining is the partial or complete loss of training-induced adaptations, in response to an insufficient training stimulus. Detraining characteristics may be different depending on the duration of training cessation or insufficient training. Short term detraining (less than 4 weeks of insufficient training stimulus) is analysed in part I of this review, whereas part II will deal with long term detraining (more than 4 weeks of insufficient training stimulus). Short term cardiorespiratory detraining is characterised in highly trained athletes by a rapid decline in maximal oxygen uptake (VO2max) and blood volume. Exercise heart rate increases insufficiently to counterbalance the decreased stroke volume, and maximal cardiac output is thus reduced. Ventilatory efficiency and endurance performance are also impaired. These changes are more moderate in recently trained individuals. From a metabolic viewpoint, short term inactivity implies an increased reliance on carbohydrate metabolism during exercise, as shown by a higher exercise respiratory exchange ratio, and lowered lipase activity, GLUT-4 content, glycogen level and lactate threshold. At the muscle level, capillary density and oxidative enzyme activities are reduced. Training-induced changes in fibre cross-sectional area are reversed, but strength performance declines are limited. Hormonal changes include a reduced insulin sensitivity, a possible increase in testosterone and growth hormone levels in strength athletes, and a reversal of short term training-induced adaptations in fluid-electrolyte regulating hormones.
This part II discusses detraining following an insufficient training stimulus period longer than 4 weeks, as well as several strategies that may be useful to avoid its negative impact. The maximal oxygen uptake (VO2max) of athletes declines markedly but remains above control values during long term detraining, whereas recently acquired VO2max gains are completely lost. This is partly due to reduced blood volume, cardiac dimensions and ventilatory efficiency, resulting in lower stroke volume and cardiac output, despite increased heart rates. Endurance performance is accordingly impaired. Resting muscle glycogen levels return to baseline, carbohydrate utilisation increases and the lactate threshold is lowered, although it remains above untrained values in the highly trained. At the muscle level, capillarisation, arterial-venous oxygen difference and oxidative enzyme activities decline in athletes and are completely reversed in recently trained individuals, contributing significantly to the long term loss in VO2max. Oxidative fibre proportion is decreased in endurance athletes, whereas it increases in strength athletes, whose fibre areas are significantly reduced. Force production declines slowly, and usually remains above control values for very long periods. All these negative effects can be avoided or limited by reduced training strategies, as long as training intensity is maintained and frequency reduced only moderately. On the other hand, training volume can be markedly reduced. Cross-training may also be effective in maintaining training-induced adaptations. Athletes should use similar-mode exercise, but moderately trained individuals could also benefit from dissimilar-mode cross-training. Finally, the existence of a cross-transfer effect between ipsilateral and contralateral limbs should be considered in order to limit detraining during periods of unilateral immobilisation.
Detraining can be defined as the partial or complete loss of training-induced adaptations, in response to an insufficient training stimulus. Detraining is characterized, among other changes, by marked alterations in the cardiorespiratory system and the metabolic patterns during exercise. In highly trained athletes, insufficient training induces a rapid decline in VO2max, but it remains above control values. Exercise heart rate increases insufficiently to counterbalance the decreased stroke volume resulting from a rapid blood volume loss, and maximal cardiac output is thus reduced. Cardiac dimensions are also reduced, as well as ventilatory efficiency. Consequently, endurance performance is also markedly impaired. These changes are more moderate in recently trained subjects in the short-term, but recently acquired VO2max gains are completely lost after training stoppage periods longer than 4 wk. From a metabolic viewpoint, even short-term inactivity implies an increased reliance on carbohydrate metabolism during exercise, as shown by a higher exercise respiratory exchange ratio. This may result from a reduced insulin sensitivity and GLUT-4 transporter protein content, coupled with a lowered muscle lipoprotein lipase activity. These metabolic changes may take place within 10 d of training cessation. Resting muscle glycogen concentration returns to baseline within a few weeks without training, and trained athletes' lactate threshold is also lowered, but still remains above untrained values.
Changes in the metabolic response to an endurance exercise were studied (18 rowing km at 75 % of maximal aerobic velocity) during detraining in ten rowers previously highly-trained. Maximal aerobic velocity (VO2 max) and the metabolic response to exercise were determined in the 1 st, 24 th, and 47 th week (training), and in the 52 nd, 76 th, and 99 th week (detraining). Over the decrease of VO2 max, detraining induced a biphasic alteration of the previously observed training adaptations: 1-short-term detraining (5 weeks) resulted in a lower adipose tissue triglyceride (TG) delivery during exercise (p = 0.029), but this one did not represent a direct metabolic limit to exercise since the liver TG delivery increased (p = 0.039), allowing that total fatty acid concentration remained unchanged (12.1 +/- 2.4 vs. 11.8 +/- 2.1 mmol/l; weeks 47 vs. 52); 2-long-term detraining (52 weeks) altered even more the metabolic response to exercise with a decreased total fatty acid concentration during exercise (week 99: 10.6 +/- 2.0 mmol/l; p = 0.022), which induced a higher glycolysis utilization. At this moment, a hemolytic response to endurance exercise was observed through haptoglobin and transferrin concentration changes (weeks 47 vs. 99; p = 0.029 and 0.027, respectively), which resulted probably from higher red blood cell destruction. Endurance-trained athletes should avoid detraining periods over a few weeks since alterations of the metabolic adaptations to training may become rapidly chronic after such delays.
The purpose of this study was to examine the efficacy of 11 wk of resistance training to failure vs. nonfailure, followed by an identical 5-wk peaking period of maximal strength and power training for both groups as well as to examine the underlying physiological changes in basal circulating anabolic and catabolic hormones. Forty-two physically active men were matched and then randomly assigned to either a training to failure (RF; n = 14), nonfailure (NRF; n = 15), or control groups (C; n = 13). Muscular and power testing and blood draws to determine basal hormonal concentrations were conducted before the initiation of training (T0), after 6 wk of training (T1), after 11 wk of training (T2), and after 16 wk of training (T3). Both RF and NRF resulted in similar gains in 1-repetition maximum bench press (23 and 23%) and parallel squat (22 and 23%), muscle power output of the arm (27 and 28%) and leg extensor muscles (26 and 29%), and maximal number of repetitions performed during parallel squat (66 and 69%). RF group experienced larger gains in the maximal number of repetitions performed during the bench press. The peaking phase (T2 to T3) after NRF resulted in larger gains in muscle power output of the lower extremities, whereas after RF it resulted in larger gains in the maximal number of repetitions performed during the bench press. Strength training leading to RF resulted in reductions in resting concentrations of IGF-1 and elevations in IGFBP-3, whereas NRF resulted in reduced resting cortisol concentrations and an elevation in resting serum total testosterone concentration. This investigation demonstrated a potential beneficial stimulus of NRF for improving strength and power, especially during the subsequent peaking training period, whereas performing sets to failure resulted in greater gains in local muscular endurance. Elevation in IGFBP-3 after resistance training may have been compensatory to accommodate the reduction in IGF-1 to preserve IGF availability.
This study examined the impact of 4 weeks of either complete cessation of training (DTR) or a tapering period (TAP; short-term reduction of the strength training volume, while the intensity is kept high), subsequent to 16 weeks of periodized heavy resistance training (PRT) on strength/power gains and the underlying physiologic changes in basal circulating anabolic/catabolic hormones in strength-trained athletes. Forty-six physically active men were matched and randomly assigned to a TAP (n = 11), DTR (n = 14), or control group (C; n = 21), subsequent to a 16-week PRT program. Muscular and power testing and blood draws to determine basal hormonal concentrations were conducted before the initiation of training (T0), after 16 weeks of training (T1), and after 4 weeks of either DTR or TAP (T2). Short-term DTR (4 weeks) results in significant decreases in maximal strength (-6 to -9%) and muscle power output (-17 and -14%) of the arm and leg extensor muscles. However, DTR had a significant (p < 0.01) larger effect on muscle power output more than on strength measurements of both upper and lower extremity muscles. Short-term (4 weeks) TAP reached further increases for leg (2%) and arm (2%) maximal strength, whereas no further changes were observed in both upper and lower muscle power output. Short-term DTR resulted in a tendency for elevation resting serum insulin-like growth factor (IGF)-1 concentrations, whereas the corresponding TAP experienced elevation in resting serum insulin-like binding protein-3 (IGFBP-3). These data indicated that DTR may induce larger declines in muscle power output than in maximal strength, whereas TAP may result in further strength enhancement (but not muscle power), mediated, in part, by training-related differences in IGF-1 and IGFBP-3 concentrations.
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