Hartshorne Matthew T, Turner Jeffrey A, Cameron Kenneth L, Padua Darin A
Human Movement Science Curriculum University of North Carolina at Chapel Hill.
Keller Army Hospital.
Int J Sports Phys Ther. 2024 Jun 1;19(6):657-669. doi: 10.26603/001c.117547. eCollection 2024.
Muscular strength deficits are common after ACL injury. While the Limb Symmetry Index (LSI), using the uninvolved limb as a reference, is widely used, negative strength adaptations may affect both limbs post-injury. It is uncertain how the strength of the uninvolved limb in those with an ACL injury compares to uninjured individuals, making it unclear whether it is appropriate as a benchmark for determining sufficient strength.
To compare the strength of key lower extremity muscles of the uninvolved limb in those with history of ACL injury (ACL-I) to the dominant limb in individuals with no history of ACL injury (control).
Cross-sectional study. Methods: A total of 5,727 military cadets were examined, with 82 females and 126 males in the ACL-I group and 2,146 females and 3,373 males in the control group. Maximum isometric strength was assessed for six muscle groups measured with a hand-held dynamometer. Separate two-way ANOVAs with limb and sex were performed for each muscle group.
Significant main effects for limb were observed with the uninvolved limb in the ACL-I group displaying greater strength compared to the dominant limb in the control group for the quadriceps, hamstrings, and gluteus medius, but effect sizes were small (Cohen's d <0.25). Significant main effects for sex were observed with greater male muscular strength in all six muscle groups with small to large effect sizes (Cohen's d 0.49-1.46). No limb-by-sex interactions were observed.
There was no evidence of reduced strength in the uninvolved limb in those with a history of ACL injury compared to the dominant limb in those with no prior ACL injury. This finding suggests that, after clearance to return to activities, the uninvolved limb can be used as a standard for comparison of sufficient strength, including when using the LSI. Level of Evidence: Level 3.
前交叉韧带（ACL）损伤后肌肉力量不足很常见。虽然以未受伤肢体为参照的肢体对称指数（LSI）被广泛使用，但损伤后负向力量适应可能会影响双侧肢体。ACL损伤患者未受伤肢体的力量与未受伤个体相比情况如何尚不确定，这使得不清楚将其作为确定足够力量的基准是否合适。
比较有ACL损伤史（ACL-I）者未受伤肢体的关键下肢肌肉力量与无ACL损伤史个体（对照组）优势肢体的力量。
横断面研究。方法：共检查了5727名军校学员，ACL-I组有82名女性和126名男性，对照组有2146名女性和3373名男性。使用手持测力计评估六个肌肉群的最大等长力量。对每个肌肉群进行肢体和性别的双向方差分析。
观察到肢体的显著主效应，ACL-I组未受伤肢体在股四头肌、腘绳肌和臀中肌方面显示出比对照组优势肢体更大的力量，但效应量较小（科恩d<0.25）。观察到性别的显著主效应，所有六个肌肉群中男性肌肉力量更大，效应量从小到大都有（科恩d 0.49 - 1.46）。未观察到肢体与性别的交互作用。
与无既往ACL损伤者的优势肢体相比，没有证据表明有ACL损伤史者的未受伤肢体力量降低。这一发现表明，在获准恢复活动后，未受伤肢体可作为足够力量比较的标准，包括在使用LSI时。证据水平：3级。
