A 2-wk taper during which training volume is exponentially reduced by 41-60% seems to be the most efficient strategy to maximize performance gains. This meta-analysis provides a framework that can be useful for athletes, coaches, and sport scientists to optimize their tapering strategy.

Objective: A meta-analysis was conducted on the effect of overload training on resting HR, submaximal and maximal exercise HR (HR), and heart rate variability (HRV), to determine whether these measures can be used as valid markers of over-reaching. Methods: Six databases were searched using relevant terms and strategies. Criteria for study inclusion were: participants had to be competitive athletes, an increased training load intervention had to be used, and all necessary data to calculate effect sizes had to be available. An arbitrary limit of 2 weeks was chosen to make the distinction between short-term and long-term interventions. Dependent variables were HR and HRV (during supine rest). Standardised mean differences (SMD) in HR or HRV before and after interventions were calculated, and weighted according to the within-group heterogeneity to develop an overall effect. Results: In these competitive athletes, short-term interventions resulted in a moderate increase in both resting HR (SMD = 0.55; p = 0.01) and low frequency/ high frequency ratio (SMD = 0.52; p = 0.02), and a moderate decrease in maximal HR (SMD = 20.75; p = 0.01). Long-term interventions resulted in a small decrease in HR during submaximal (SMD = 20.38; p = 0.006) and maximal exercise (SMD = 20.33; p = 0.007), without alteration of resting values. Conclusion: The small to moderate amplitude of these alterations limits their clinical usefulness, as expected differences may fall within the day-to-day variability of these markers. Consequently, correct interpretation of HR or HRV fluctuations during the training process requires the comparison with other signs and symptoms of overreaching to be meaningful.Peak performance in sport requires training loads that will occasionally push the adaptation capabilities of the human body to their limits. If significant improvements are expected when sufficient recovery is allowed before competition, 1 2 athletes may also experience unexplained underperformance.3 4 Various terms have been used in the scientific literature over the past decades to describe this disruption in the training adaptation process. In an effort to clarify the terminology, the Task Force of the European College of Sports Science distinguished functional over-reaching (FOR), non-functional over-reaching (NFOR) and overtraining syndrome (OTS) to mark out the continuum that leads to long-term underperformance. Over-reaching refers to an accumulation of training and/or non-training stress resulting in short-term decrease in performance capacity with or without related physiological and psychological signs and symptoms of overtraining, in which restoration of performance capacity may take several days to several weeks.5-7 FOR is occasionally used by athletes during a typical training cycle. An improvement in performance capacity above what would be achievable after a normal training cycle is expected if the athlete is allowed sufficient recovery to permit the occurrence of the supercompensation effect. As suggested by Meeusen et al...

The purpose of this study was to assess the effect of resistance training cessation on strength performance through a meta-analysis. Seven databases were searched from which 103 of 284 potential studies met inclusion criteria. Training status, sex, age, and the duration of training cessation were used as moderators. Standardized mean difference (SMD) in muscular performance was calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Results indicated a detrimental effect of resistance training cessation on all components of muscular performance: [submaximal strength; SMD (95% CI) = -0.62 (-0.80 to -0.45), P < 0.01], [maximal force; SMD (95% CI) = -0.46 (-0.54 to -0.37), P < 0.01], [maximal power; SMD (95% CI) = -0.20 (-0.28 to -0.13), P < 0.01]. A dose-response relationship between the amplitude of SMD and the duration of training cessation was identified. The effect of resistance training cessation was found to be larger in older people (> 65 years old). The effect was also larger in inactive people for maximal force and maximal power when compared with recreational athletes. Resistance training cessation decreases all components of muscular strength. The magnitude of the effect differs according to training status, age or the duration of training cessation.

Taken together, these results provide a framework that supports the implementation of strength training in addition to traditional sport-specific training to improve middle- and long-distance performance, mainly through improvements in the energy cost of locomotion, maximal power, and maximal strength.

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