Bioengineering and Biomechanics Laboratory, Federal University of Goias, Avenida Esperança s/n, Campus Samambaia, Goiania, Goiás, 74.690-900, Brazil.
State University of Goias-Campus Trindade, Trindade, GO, 75.386-580, Brazil.
Med Biol Eng Comput. 2020 Aug;58(8):1791-1802. doi: 10.1007/s11517-020-02196-8. Epub 2020 Jun 5.
Muscle fatigue negatively affects gait, and the changes in gait pattern due to muscle fatigue is influenced by which muscles are fatigued and pre-existing physical activity levels. However, how these factors alter gait stability and variability, measures related to risk of fall, remains unclear. To explore how muscular fatigue affects linear and nonlinear gait features in young adults, the effects of triceps surae fatigue and weight training level on gait variability and local stability, as well as a 12-min recovery time of post-fatigue period, were evaluated in young adults (trained and untrained groups). Some features were estimated, i.e., (i) step length (SL) and step frequency (SF), (ii) average standard deviation of trunk acceleration along strides (VAR), and (iii) local dynamic stability (LDS; maximum Lyapunov exponent). LDS presented a significant increase in the anterior-posterior direction with recovery to trained group. SL and SF changed immediately post-fatigue and recovered for both groups, while VAR increased significantly in all directions, with a recovery in the vertical direction for both groups and in the medial-lateral direction for trained group. Localized fatigue affected the analyzed gait variables independent of the participant's training condition, and an interval of 12 min does not seem to be enough for a complete recovery, suggesting a longer recovery period after tasks involving localized triceps surae fatigue to guarantee basal levels of gait variability and local stability. Graphical abstract Flow chart of the experimental protocol. A) Pre-fatigue: 4 min walking at PWS. B) Post-fatigue: first 4 min walking after fatigue protocol. C) Post-fatigue: second 4 min walking after fatigue protocol. D) Post-fatigue: third 4 min walking after fatigue protocol (PWS, preferred walking speed; AP, anterior-posterior; V, vertical; ML, medial-lateral).
肌肉疲劳会对步态产生负面影响，而由于肌肉疲劳导致的步态模式变化受到疲劳的肌肉以及先前的身体活动水平的影响。然而，这些因素如何改变步态稳定性和可变性，即与跌倒风险相关的测量指标，目前还不清楚。为了探讨肌肉疲劳如何影响年轻人的线性和非线性步态特征，研究评估了小腿三头肌疲劳和举重训练水平对年轻人步态变异性和局部稳定性的影响，以及疲劳后 12 分钟的恢复期。评估了一些特征，即（i）步长（SL）和步频（SF），（ii）沿步长的躯干加速度的平均标准偏差（VAR），以及（iii）局部动态稳定性（LDS；最大 Lyapunov 指数）。LDS 在恢复到训练组后在前后方向上呈现出显著增加。SL 和 SF 在疲劳后立即发生变化并在两组中恢复，而 VAR 在所有方向上都显著增加，两组在垂直方向上恢复，而训练组在横向方向上恢复。局部疲劳会独立于参与者的训练状况影响分析中的步态变量，并且 12 分钟的间隔似乎不足以完全恢复，这表明在涉及小腿三头肌局部疲劳的任务后需要更长的恢复时间，以保证步态变异性和局部稳定性的基本水平。
