Back squat velocity to assess neuromuscular status of rugby league players following a match

Abstract

Objectives: Back squat mean concentric velocity (MV) and countermovement jump (CMJ) performance were examined in sub-elite rugby league players post-match to monitor changes in neuromuscular status (NMS) from baseline. Relationships between changes in back squat MV and CMJ performance variables were used to compare back squat MV to an established method to monitor NMS. Design: Longitudinal observational design. Methods: 18 male sub-elite rugby league players (mean ± SD, 20.5 ± 2.4 yr; 180.0 ± 6.7 cm; 93.3 ± 11.2 kg) performed 3 repetitions of CMJ and back squat with an individualised, predetermined load at −2 h (baseline), +30 min, +24 h, and +48 h in relation to a match. Back squat MV, CMJ height, CMJ peak power, and CMJ peak velocity were measured with a linear position transducer. Results: Significant (p < 0.05), small to large decreases (ES = 0.52-1.24) were observed in back squat MV up to +48 h post-match. Significant (p < 0.05), small to moderate decreases (ES = 0.52-0.70) in CMJ height were also observed up to +24 h post-match, returning to baseline at +48 h. CMJ peak power and peak velocity post-match changes were not significant compared to baseline (p > 0.05). Significant positive correlations were found between changes in back squat MV and CMJ height at +30 min (r = 0.59; p = 0.009) and +48 h (r = 0.51; p = 0.03). Conclusions: These findings suggest back squat MV may be a suitable alternative or addition to CMJ testing for monitoring NMS in rugby league players.

What Is the Most Sensitive Test to Identify Fatigue through the Analysis of Neuromuscular Status in Male Elite Futsal Players?

“…In the back squat, two aspects produced greater demands on the muscles of the lower body in comparison with the countermovement jump test [ 51 , 52 ]: (1) the higher force required to overcome an additional load; and (2) the higher range of movement imposed which produced an increase in stretching and longer concentric duration. These results are similar to those reported by Callaghan et al [ 17 ], which suggested that the additional load in the back squat may impose higher requirements on the muscles of the lower body in sub-elite level rugby players. Considering this previous factor and the direct recruitment of the most fatigued muscles during a futsal match [ 7 , 42 , 46 ], the monitoring of the NMS through the back squat provides greater sensitivity and objectivity than the countermovement jump.…”

“…Player fatigue can be monitored using biochemical (e.g., creatine kinase, lactate dehydrogenase, oxidative stress markers) [ 11 , 12 ], physiological (e.g., heart rate variability, heart rate recovery index) [ 13 , 14 ], psychological (e.g., rating of perceived exertion, athlete self-report measures, profile of mood states, total recovery scale) [ 4 , 15 , 16 ] and physical performance variables [ 11 , 17 , 18 , 19 ]. Although physical performance can be evaluated through multiple performance tests (Yo-Yo test, repeated sprint ability, 5 m and 20 m sprint, t -test) [ 2 , 20 ], the evaluation of the neuromuscular status (NMS) in athletes offers objective and useful quantifiable results [ 21 ] without the need to invest too much time for it.…”

“…Previous studies reported a strong negative correlation between execution velocity and relative loads based on one repetition maximum (1RM) [ 28 , 29 ]. In addition, by knowing the load-velocity profile of an athlete, it is possible to determine velocity loss associated with a given load after training or competitive events [ 17 ]. Therefore, the bar velocity loss during resistance exercise can be used in combination with countermovement jump variables to evaluate changes in NMS after fatiguing episodes [ 30 , 31 ].…”

“…The countermovement jump has been used extensively to quantify neuromuscular fatigue in team sports [ 17 , 22 , 24 , 33 ]. However, as far as we know, bar velocity in the squat exercise to quantify neuromuscular fatigue has been performed only in official rugby matches [ 17 ].…”

“…The countermovement jump has been used extensively to quantify neuromuscular fatigue in team sports [ 17 , 22 , 24 , 33 ]. However, as far as we know, bar velocity in the squat exercise to quantify neuromuscular fatigue has been performed only in official rugby matches [ 17 ]. If the velocity of the barbell in the loaded back squat exercise proves to be sensitive enough to identify states of acute fatigue based on changes in the NMS, it would represent an advance in the economy of training time, since such an exercise could be integrated into strength training programs while monitoring the state of fatigue of athletes.…”