Recovery of muscle function following strength training in rowers

Strength training using free weights is performed by athletes in many sports as a means of enhancing performance. However, there is a dearth of research investigating the acute impact of bouts of this form of strength training on muscle function, which closely mimics the athletes’ sport or event. High forces are produced during a rowing race and subsequently strength training forms an integral part of the overall training programme for rowers. However, there is little documented evidence regarding the strength and conditioning practices occurring in rowing. Therefore the aims of this thesis were to investigate and draw conclusions regarding the strength and conditioning practices occurring within British rowing and to evaluate the impact of typical bouts of strength training on muscle function in rowers. To investigate the strength and conditioning practices within British rowing a questionnaire was completed by 32 coaches and semi-structured interviews were undertaken with two coaches of elite rowers (study 1). Information from both sources indicated that rowers performed two to three strength training sessions per week, involving Olympic lifting and multi-joint free weight strength exercises, performed across multiple sets with low to moderate repetition ranges. Physical testing most commonly involved assessment of cardiovascular endurance, muscular power and strength. Twenty four hours of recovery were generally afforded between strength training and intensive rowing training while longer periods were permitted before rowing races (> 48 h). Prior to the intervention studies, the reproducibility of subsequently assessed measures was assessed using trained rowers (study 2). Typical error (%) was low for 2000 m mean power (2.4 %), and low to moderate for the assessments of strength and power (3.0-5.9 %). Measures of peak blood lactate (11.5 %), creatine kinase (21.0 %) and surface electromyography (11.1-44.8 %, across various sites) demonstrated greater variability similar to previous studies. For studies 3 and 4, trained rowers performed 250 m and 2000 m rowing tests respectively, alongside various measures of muscle function before and after an acute bout of free weight multi-joint strength training (ST). For both studies, increases in perceived muscle soreness and CK indicated that muscle damage was present after ST for 24-48 h. Maximal power generating ability was decreased in both studies as evidenced by decrements in the 250 m test, power strokes, and jump height. However, in study 4, 2000 m rowing time was unaffected, leading to the conclusion that the specific muscle function required for the power tests was affected through damage to type II muscle fibres. Findings from study 1 indicated that rowers commonly perform strength training three times per week; therefore study 5 investigated the impact of this weekly frequency of strength training on muscle function. Twenty four hours after three bouts of ST within a five day period, trained rowers experienced significant decreases in maximal voluntary contraction, jump height and power stroke tests as well as increases in CK and soreness; however as with study 4, 2000m performance was unaffected. Trends for decreases in peak lactate and anaerobic energy liberation (p < 0.10, Effect Size = 0.40-0.56) were present alongside significant increases in EMG at three sites during the post-ST 2000 m test. These findings suggest a decreased utilisation of the anaerobic capacity coupled with increased central motor drive suggesting a change in muscular recruitment patterns during the follow up 2000 m rowing test. It would appear that following extensive strength training, physiological processes were adapted during subsequent rowing exercise, to compensate for the loss in higher threshold muscle fibre function, in order to affect the same level of rowing performance achieved in the rested state. These findings might suggest that participants operated within a physiological reserve and/or that multiple-exercise-regulation-algorithms exist with which a similar exercise performance can be achieved.