Seasonal variation of physical performance and inter-limb asymmetry in professional cricket athletes

The aims of the present study were to: 1) determine the seasonal variation of physical performance in professional cricket players, 2) determine the seasonal variation of inter-limb asymmetries in the same cohort of professional players. Fifteen male professional cricket players (age: 20.60 ± 1.59 years; height: 1.82 ± 0.08 m; body mass: 78.70 ± 11.23 kg) performed unilateral countermovement jumps (CMJ), unilateral drop jumps, 10m sprints and 505 change of direction (COD) speed tests at pre (March), mid (June) and end (September) of the 2018 season. Inter-limb asymmetry was quantified in the unilateral CMJ (jump height and concentric impulse), unilateral drop jump (jump height and reactive strength index – RSI) and 505 (total time and COD deficit). Significant changes (p < 0.05) were evident for the following tests: unilateral CMJ (ES range = 0.67 to 1.00), 505 on the right leg (ES = 0.70), 10m (ES range = -1.39 to 0.70) and COD deficit (ES range = 0.70 to 0.80), with the largest changes evident for 10m sprint. No significant differences were evident in drop jump performance throughout the season. For the magnitude of asymmetry, significant changes in jump height asymmetry from the unilateral CMJ were evident from mid to end of season (ES = 0.72). For the direction of asymmetry, levels of agreement ranged from poor to substantial in the unilateral CMJ (Kappa = -0.21 to 0.72), fair to substantial in the unilateral drop jump (Kappa range = 0.33 to 0.74) and slight to moderate during the 505 test (Kappa range = 0.06 to 0.44), with RSI showing noticeably better results than other tests or metrics. These data shows that the largest changes in performance scores throughout the season came from the 10m test, which practitioners may wish to consider implementing if not doing so already. Furthermore, both unilateral jump tests showed their use for asymmetry interpretation, which practitioners may wish to consider implementing in to their test batteries. Specifically, jump height asymmetry during the unilateral CMJ was the only metric to exhibit meaningful changes between time points, whilst RSI was the metric that exhibited more consistent limb dominance characteristics for the direction of asymmetry