The Reliability of Functional Movement Screening and In-Season Changes in Physical Function and Performance Among Elite Rugby League Players

Waldron, M, Gray, A, Worsfold, P, and Twist, C. The reliability of functional movement screening and in-season changes in physical function and performance among elite rugby league players. J Strength Cond Res 30(4): 910-918, 2016-This study aimed to (a) assess the reliability of the functional movement screening (FMS) protocol and (b) to establish changes in both FMS and tests of physical performance throughout a season. The reliability of the FMS components (12 in total) was assessed through a nonparametric statistical approach, based on 2 trials, separated by 1 week. Score on the FMS, strength (3 repetition maximum full squat, 1 repetition maximum [1 RM] bench press), running speed (10 and 40 m), and jump height of 12 elite male under-19 rugby league players was monitored at pre-, mid-, and late-season periods. There was no bias (p > 0.05) found between trials for the FMS, with the majority of components reaching 100% "perfect agreement," reflecting the good reliability of the FMS tool. There were no effects (p > 0.05) of season stage on any of the FMS components; however, an improvement (p <= 0.05) between the pre- and both mid- and late-season periods was apparent in every component of fitness, such as 1 RM bench press (112.92 +/- 24.54 kg; 125.83 +/- 21.41 kg; 125.98 +/- 24.48 kg) and 40-m sprint time (5.69 +/- 0.35 seconds; 5.62 +/- 0.31 seconds; 5.64 +/- 0.27 seconds). Our findings demonstrate that the FMS can be reliably administered to elite rugby league players but will not change in accordance with physical performance across a competitive season. Our findings should not necessarily deter practitioners from using the FMS but begin to question the specific qualities that are being assessed through its administration.