Limitations in intense exercise performance of athletes – effect of speed endurance training on ion handling and fatigue development

Abstract

Mechanisms underlying fatigue development and limitations for performance during intense exercise have been intensively studied during the past couple of decades. Fatigue development may involve several interacting factors and depends on type of exercise undertaken and training level of the individual. Intense exercise (½-6 min) causes major ionic perturbations (Ca , Cl , H , K , lactate and Na ) that may reduce sarcolemmal excitability, Ca release and force production of skeletal muscle. Maintenance of ion homeostasis is thus essential to sustain force production and power output during intense exercise. Regular speed endurance training (SET), i.e. exercise performed at intensities above that corresponding to maximum oxygen consumption (V̇O2, max ), enhances intense exercise performance. However, most of the studies that have provided mechanistic insight into the beneficial effects of SET have been conducted in untrained and recreationally active individuals, making extrapolation towards athletes' performance difficult. Nevertheless, recent studies indicate that only a few weeks of SET enhances intense exercise performance in highly trained individuals. In these studies, the enhanced performance was not associated with changes in V̇O2, max and muscle oxidative capacity, but rather with adaptations in muscle ion handling, including lowered interstitial concentrations of K during and in recovery from intense exercise, improved lactate -H transport and H regulation, and enhanced Ca release function. The purpose of this Topical Review is to provide an overview of the effect of SET and to discuss potential mechanisms underlying enhancements in performance induced by SET in already well-trained individuals with special emphasis on ion handling in skeletal muscle.

Sweat Rate Measurements After High Intensity Interval Training Using Body Weight

“…22 Besides, the intensity of stimuli as well as the physical fitness level also influences directly in the response of these control mechanisms. 23 Although it is simple, the alteration of body mass after physical exercise has been considered a suitable parameter to assess dehydration.…”

Metabolic stress‐dependent regulation of the mitochondrial biogenic molecular response to high‐intensity exercise in human skeletal muscle

“…In recent years, a growing body of research has focused on specific forms of intense interval training characterized by short‐duration maximal/supramaximal efforts (Bishop et al . 2011; Hostrup & Bangsbo, ). In this context, speed endurance exercise training, depicted as multiple prolonged “all‐out” bouts (<40 s) separated by comparatively long resting periods (Iaia & Bangsbo, ), has been shown to promote increments in the activity and/or content of muscle mitochondrial enzymes together with improvements in endurance exercise performance (Burgomaster et al .…”

“…High-intensity interval training, defined as repeated intense work bouts separated by recovery periods, is broadly recognized as a time-efficient alternative to traditional endurance exercise training for promoting skeletal muscle remodelling and enhancing exercise performance (Laursen & Jenkins, 2002;MacInnis & Gibala, 2017). In recent years, a growing body of research has focused on specific forms of intense interval training characterized by short-duration maximal/supramaximal efforts Hostrup & Bangsbo, 2017). In this context, speed endurance exercise training, depicted as multiple prolonged "all-out" bouts (<40 s) separated by comparatively long resting periods (Iaia & Bangsbo, 2010), has been shown to promote increments in the activity and/or content of muscle mitochondrial enzymes together with improvements in endurance exercise performance (Burgomaster et al 2005;Little et al 2010;Hostrup et al 2018).…”

In‐season adaptations to intense intermittent training and sprint interval training in sub‐elite football players

“…[4][5][6] An effective strategy to enhance football-specific performance is intense intermittent exercise training performed at supramaximal intensity (ie, running velocities above that corresponding to maximal oxygen consumption (VO 2max )). [7][8][9] In active individuals, improvements in performance are closely related to the training modality undertaken, 10,11 suggesting that training specificity is important. Sub-elite football players, training 2-3 times per week, have limited time available to train the technical, tactical, and physical aspects required in football.…”

“…Studies show that intense intermittent training comprising of long-duration sprints (~30second) with relatively long recovery periods (work:rest ratio of ~1:6) improves intermittent exercise capacity. 7,8 However, in trained football players, speed endurance training does not necessarily enhance sprint performance. 12 On the other hand, shorter duration all-out sprints (≤10 seconds), conducted in conjunction with a high aerobic load, may improve intermittent exercise capacity, but it is unknown whether such training regime also improves sprint performance, as expected by traditional sprint training with short all-out sprints (~6 seconds) with long recovery periods.…”