Effects of Training Load Changes on Physical Performance and Exercise-Induced Muscle Damage

Abstract

Introduction There is no previous study examining muscle damage responses from training load changes in individuals trained exclusively with repeated sprint exercise. Objectives The purpose of this study was to examine the effect of training load changes on physical performance and exercise-induced muscle damage in male college athletes who were trained using a 30m repeated sprint protocol. Methods Twelve participants completed the 6-week training period (three sessions/week), which consisted of progressively increasing intensity training in the first 5 weeks. On the first day of the training period, all sprints were performed at 70–80% of maximum effort. In the first session of the 5th week (Maximal intensity training; MIT), all sprints (10×30m sprints) were performed at maximal speed. The sets (10 sprints at maximal speed in each set) were repeated until exhaustion (Exhaustive training; ET) in the first training session of the 6th week, followed by two sessions of the normal training. Isometric strength, 30m sprint performance, flexibility, serum creatine kinase (CK) and cortisol were measured periodically during the examination period. Results Isometric strength, 30m sprint performance, and flexibility were significantly decreased following the ET, and did not recover during the following 9-day period, which consisted of two training sessions and 6 days of recovery. Cortisol was significantly elevated immediately after the ET but was not changed after training on first day and during MIT. CK was significantly elevated after training every week, but the increase at 24 hours after ET was significantly higher than after the first day and MIT. Conclusions Dramatically increasing the volume of maximal intensity repeated sprint exercise results in greater relative muscle damage even in trained individuals, which will significantly limit their performance. Further training sessions, even at normal intensity and volume with insufficient time for muscle recovery, may prolong the duration of fatigue. Level of evidence II; Diagnostic Studies - Investigating a diagnostic test.

Acute effect of HIIT on testosterone and cortisol levels in healthy individuals: A systematic review and meta‐analysis

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The Acute Demands of Repeated-Sprint Training on Physiological, Neuromuscular, Perceptual and Performance Outcomes in Team Sport Athletes: A Systematic Review and Meta-analysis

“…We acknowledge that the residual effects of intense exercise may last up to 72 h [ 32 ], but acute demands measured up to 24 h following RST was selected because: (a) it is common for RST and other team sport activity to be interspersed with minimal recovery time (i.e. < 72 h), (b) pilot scoping of the literature only identified five studies [ 33 – 37 ] that recorded measurements on athletes > 24 h. Several studies/protocols were excluded from this investigation that implemented repeated-sprint sequences with sport skill elements [ 38 – 42 ] or involved a reactive component in response to an external stimulus (e.g. light sensor) [ 43 – 46 ].…”