Muscle fiber typology is associated with the incidence of overreaching in response to overload training

Abstract

The aim of this study was to identify markers of training stress and characteristics of middle-distance runners related to the incidence of overreaching following overload training. Twenty-four highly-trained runners (n=16 male; VO2peak=73.3(4.3) mL·kg·min-1; n=8 female, VO2peak=63.2(3.4) mL·kg·min-1) completed 3 weeks of normal training (NormTr), 3 weeks of high-volume training (HVTr; a 10, 20 and 30% increase in training volume each successive week from NormTr), and a 1-week taper (TapTr; 55% exponential reduction in training volume from HVTr week 3). Before, and immediately after each training period, an incremental treadmill-running test was performed, while resting metabolic rate (RMR), subjective fatigue responses and various resting blood biomarkers were assessed. Muscle fiber typology of the gastrocnemius was estimated by quantification of muscle carnosine using proton magnetic resonance spectroscopy and expressed as a z-score relative to a non-athlete control group. Twelve runners were classified as functionally overreached (FOR) following HVTr (decreased running TTE), whereas the other twelve were classified as acutely fatigued (AF; no decrease in running TTE). The FOR group did not demonstrate systematic alterations in RMR, resting blood biomarkers or submaximal exercise responses compared to the AF group. Gastrocnemius carnosine z-score was significantly higher in FOR (-0.44 ± 0.57) compared to AF (-1.25 ± 0.49, p = 0.004, d = 1.53) and was also associated with changes in running TTE from pre- to post-HVTr (r=-0.55, p=0.005) and pre-HVTr to post-TapTr (r=-0.64, p=0.008). Muscle fiber typology is related to the incidence of overreaching and performance super-compensation following increased training volume and a taper.

Individualized Endurance Training Based on Recovery and Training Status in Recreational Runners

“…The training was periodized in a way that 2 intensive weeks were followed by 1 recovery week. The training volume progression was similar to previous studies ( 7 , 25 ): during intensive weeks, it increased by 10% compared with the baseline level (2 first weeks of PREP). To ensure sufficient recovery, training volume was always decreased by 25% after 2 intensive weeks ( 26 ).…”

Crossing the Golden Training Divide: The Science and Practice of Training World-Class 800- and 1500-m Runners

“…The majority of training intervention studies demonstrate that considerable variability in adaptation to a given exercise stimulus is the norm [e.g., [115][116][117]. The principle of individualization refers to the notion that training prescription must be adapted and optimized according to individual predispositions (performance level, training status/age, sex, recovery/injury status and physiological and structural/mechanical profiles) to maximize the effect and avoid non-responder outcomes [13,52,58,98,118]. Total training load is typically higher in well-trained adult runners of higher performance standard compared to their younger, less trained and lower-performing counterparts [19-21, 56, 58].…”

“I Want to Create So Much Stimulus That Adaptation Goes Through the Roof”: High-Performance Strength Coaches' Perceptions of Planned Overreaching

“…Previous research has indicated that there is not only variability in the physiological response to different approaches to POR training (e.g., high-volume vs. high-intensity) (Fry and Kraemer, 1997 ; Bell et al, 2020 ; Grandou et al, 2020b ), but that differences might also occur in a group of individual athletes undertaking the same training protocol. These differences are likely to be modulated by multiple factors including genotype (Clarkson et al, 2005 ), sex differences (Hunter, 2016 ) muscle fiber typology (Bellinger et al, 2020 ; Lievens et al, 2020 ), age, and biological maturation (Moran et al, 2017 ). Additional factors such as level of competition/status (elite vs. non-elite) (Kreher and Schwartz, 2012 ) and the athlete's “stress capacity” (i.e., the ability to tolerate the combined effects of training and non-training stressors) (Kenttä and Hassmén, 1998 ; Stults-Kolehmainen and Bartholomew, 2012 ) are also likely to play a role in the response to POR.…”