Abstract：
UNASSIGNED: Helme, M, Emmonds, S, Low, C, and Till, K. A novel case study approach to the investigation of leg strength asymmetry and Rugby League player\'s multidirectional speed. J Strength Cond Res 38(5): 941-947, 2024-Leg strength and multidirectional speed qualities have repeatedly been linked with increased performance during Rugby League (RL) match play and associated with career attainment. However, very little of this evidence for strength has been gained through unilateral measurements with no study available that has examined the impact of strength asymmetry, in this population, on speed qualities in RL players. Therefore, this study examined the association between unilateral strength, and as a novel development, the subject with the most extreme asymmetry was identified for further analysis. Fifty RL players undertook the rear foot elevated split squat 5 repetition maximum, 20-m linear sprint, and modified 505 change of direction test. The mean leg strength for the group was 88.92 ± 12.59 kg; when divided by body mass, the mean relative strength (REL) was 1.03 ± 0.17 kg·kg -1 , and the mean asymmetry was 3.21 ± 5.70%. The subject with the greatest asymmetry (subject A) had an imbalance of 33% and a mean leg strength of 75 kg (REL = 0.78 kg·kg -1 ) and a body mass 1 SD above the group mean. Analysis of the group\'s data and that of subject A did not indicate that leg strength asymmetry was either frequent or harmful, with respect to speed performance. However, relative leg strength was associated with both improved linear and multidirectional speed. Practitioners are recommended to prioritize the development of relative leg strength and disregard the aspiration for between leg performance symmetry.
摘要：
■赫尔默，M,恶魔，S,Low,C,直到,K.一种新颖的案例研究方法，用于调查腿部力量不对称性和橄榄球联盟球员的多向速度。JStrengthCondResXX（X）：000-000，2023年-腿部力量和多向速度素质一再与橄榄球联盟（RL）比赛中的表现提高有关，并与职业成就有关。然而,很少有这种强度的证据是通过单边测量获得的，没有研究可以检查强度不对称性的影响，在这个人口中，RL球员的速度素质。因此,这项研究检查了单边力量之间的关系，作为一种新颖的发展，我们确定了最不对称的受试者进行进一步分析.50名RL球员进行了后脚高开深蹲5次重复，20米线性冲刺，并修改了505变向试验。该组的平均腿部力量为88.92±12.59kg；当除以体重时，平均相对强度（REL）为1.03±0.17kg·kg-1，平均不对称性为3.21±5.70％。具有最大不对称性的受试者（受试者A）的失衡率为33％，平均腿部力量为75kg（REL=0.78kg·kg-1），体重高于组平均值1SD。对该组的数据和受试者A的数据的分析没有表明腿部力量不对称是常见的或有害的，关于速度性能。然而,相对腿部力量与改善的线性和多向速度相关。建议从业者优先考虑相对腿部力量的发展，而忽略腿部表现对称性之间的渴望。
