Author(s): BELLINGER, P., ROBERTS, L., MORRIS, K., DERAVE, W., LIEVENS, E., KENNEDY, B., CHARLES, J., WACKWITZ, T., MCGILL, A., DUHIG, S., Institution: GRIFFITH UNIVERSITY, Country: AUSTRALIA, Abstract-ID: 1524

INTRODUCTION:
Elite rowers present with diverse physiological profiles (van der Zwaard et al. 2018; Fukuda et al. 2011; Alföldi et al. 2021) which may be due to, in part, variation in the underpinning muscle characteristics, such as muscle oxidative capacity, architecture, volume, typology and strength. Nonetheless, the extent to which these muscle characteristics explain rowing performance has not been determined in a systematic manner previously. In this study, we aimed to identify the skeletal muscle determinants of rowing performance and pacing in elite rowers.
METHODS:
22 well-trained rowers (13 male) completed a 7-stage incremental rowing ergometer test to determine rowing economy, the lactate threshold, lactate turn point and VO2peak. The final stage of the incremental test was a maximal effort, representing a 4-min time-trial and was recorded as the criterion dependent variable (i.e., 4 min TT). We also expressed the relative distance that was covered in each minute of the 4 min TT to investigate pacing strategy. Rowers also completed a series of strength and power assessments including loaded and unloaded squat jumps, an isometric mid-thigh pull and 1-repetition maximum (RM) pull up and 3-RM leg press. Rowers underwent an assessment of body composition by dual-energy x-ray absorptiometry, magnetic resonance imaging of their thigh to determine volumes of the major hip- and knee-spanning muscle functional groups and diffusion tensor imaging to estimate muscle fascicle lengths, pennation angles and physiological cross-sectional area of the vastus lateralis (VL). Carnosine content was quantified by proton magnetic resonance spectroscopy in the soleus and expressed as a Z-score to estimate muscle typology. Data were analysed using multiple stepwise regression analysis.
RESULTS:
The majority of rowers had negative Z-score values (17/22; Z-score = -0.44 ± 0.85), indicative of a greater estimated proportion of type I fibres, with similar variation in both male and female rowers. Male rowers had greater normalized knee extensor muscle volume (19.2 cm3·kg−1) compared to female rowers (16.8 cm3·kg−1), while VL fascicle lengths were similar. When controlling for lean body mass and sex, muscle fascicle length in the VL, VO2peak and isometric mid-thigh pull peak force explained 82% of the variation in final stage of the incremental test (i.e., 4 min TT). Muscle typology was the only muscle characteristic that explained variation in pacing strategy, whereby rowers with a higher Z-scores (i.e., greater estimated proportion of type II fibres) started the 4 min TT more conservatively but covered a greater relative distance during the second half.
CONCLUSION:
In the context our study, these findings indicate that rowers should focus on increasing VL fascicle length, isometric mid-thigh pull strength and aerobic power. Muscle typology was associated with preferential pacing strategies and could be used to inform optimal boat crew pairings to maximise pacing and performance.