Department of Sports and Sport Science, University of Freiburg, Freiburg, Germany.
Praxisklinik Rennbahn AG, Muttenz, Switzerland.
PLoS One. 2022 Dec 1;17(12):e0277949. doi: 10.1371/journal.pone.0277949. eCollection 2022.
Muscle strain injuries (MSIs) in the hamstrings are among the most prevalent injuries in elite soccer. We aimed to examine the relation between biomechanical maladaptation in eccentric strength and neuromuscular factors separated by their time and frequency domains.
20 elite soccer players with a previous history of unilateral MSI in the M. biceps femoris (BF) long head and 20 without MSI participated. Knee flexion torques, rate of torque development (RTD) and electromyographic signals (EMG) of the BF, the M. semitendinosus (SMT) and knee extensors were obtained during unilateral maximal eccentric knee flexions performed at slow (30°/s) and fast (120°/s) angular speeds. Root mean squares and mean power frequency (MF) was calculated.
In the group with a history of MSI, reduced maximal eccentric flexion torque (slow eccentrics -8±11, p<0.05; fast eccentrics -18±13 Nm, p<0.05) and RTD (-33±28 Nm/s, p<0.05; -95±47 N*m/s, p<0.05) concomitantly occurred with diminished agonistic myoelectrical activities (-4±5% of MVC, p<0.05; -10±7% of MVC, p<0.05) and MFs (-24±13 Hz, p<0.05; -24±18 Hz, p<0.05) in the BF. Simultaneously, antagonistic myoelectric activity was elevated (+4±3% of MVC, p<0.05; +3±3% of MVC, p<0.05) in MSI affected legs as compared to unaffected legs for both eccentric contractions. Deficits in myoelectrical activity (r2 = 0.715, p<0.05; r2 = 0.601, p<0.05) and MF (r2 = 0.484, p<0.05; r2 = 0.622, p<0.05) correlated with deficits in maximal torque in the affected leg in the MSI group. Analysis of SMT demonstrated no significant differences.
Positive relationships between neuromuscular deficits and the reduced eccentric strength profile underpin neuronal inhibition after MSI. This persistent involvement of dysfunctional synergist and antagonist neural hamstring function in strength weakness is of clinical relevance in sports medicine for prevention and rehabilitation.
腘绳肌肌肉拉伤（MSIs）是精英足球中最常见的损伤之一。我们旨在研究离心强度的生物力学适应不良与神经肌肉因素之间的关系，这些因素按其时间和频率域分开。
20 名有单侧腘绳肌长头（BF）MSI 病史的精英足球运动员和 20 名无 MSI 的运动员参加了这项研究。在以 30°/s 和 120°/s 的角速度进行单侧最大离心膝关节屈曲时，获得了膝关节屈曲扭矩、扭矩发展率（RTD）和 BF、M.半腱肌（SMT）和膝关节伸肌的肌电图（EMG）信号。计算了均方根和平均功率频率（MF）。
在有 MSI 病史的组中，最大离心屈曲扭矩降低（慢离心-8±11，p<0.05；快离心-18±13 Nm，p<0.05）和 RTD 降低（-33±28 Nm/s，p<0.05；-95±47 N*m/s，p<0.05）同时伴有运动神经电活动减少（-4±5%的 MVC，p<0.05；-10±7%的 MVC，p<0.05）和 MF 降低（-24±13 Hz，p<0.05；-24±18 Hz，p<0.05）在 BF 中。同时，与未受影响的腿相比，MSI 受影响腿的拮抗肌电活动在两种离心收缩中均升高（+4±3%的 MVC，p<0.05；+3±3%的 MVC，p<0.05）。电活动（r2 = 0.715，p<0.05；r2 = 0.601，p<0.05）和 MF（r2 = 0.484，p<0.05；r2 = 0.622，p<0.05）的缺陷与 MSI 组受影响腿的最大扭矩缺陷相关。对 SMT 的分析未显示出显着差异。
MSI 后神经元抑制的神经肌肉缺陷与离心强度特征的降低之间存在正相关关系。这种持续存在的功能障碍协同肌和拮抗肌神经功能在运动医学中的力量减弱方面具有临床相关性，可用于预防和康复。
