Changes in knee mechanics following anterior cruciate ligament (ACL) reconstruction are known to be magnified during more difficult locomotor tasks, such as when descending stairs. However, it is unclear if increased task difficulty could distinguish differences in forces generated by the muscles surrounding the knee. This study examined how knee muscle forces differ between individuals with ACL reconstruction with different graft types (hamstring tendon and patellar tendon autograft) and "healthy" controls when performing tasks with increasing difficulty. Dynamic simulations were used to identify knee muscle forces in 15 participants when walking overground and descending stairs. The analysis was restricted to the stance phase (foot contact through toe-off), yielding 162 separate simulations of locomotion in increasing difficulty: overground walking, step-to-floor stair descent, and step-to-step stair descent. Results indicated that knee muscle forces were significantly reduced after ACL reconstruction, and stair descent tasks better discriminated changes in the quadriceps and gastrocnemii muscle forces in the reconstructed knees. Changes in quadriceps forces after a patellar tendon graft and changes in gastrocnemii forces after a hamstring tendon graft were only revealed during stair descent. These results emphasize the importance of incorporating sufficiently difficult tasks to detect residual deficits in muscle forces after ACL reconstruction.
In the article Kawakami W, Takahashi M, Iwamoto Y, Shinkoda K. Coordination among shank, rearfoot, midfoot, and forefoot kinematic movement during gait in individuals with hallux valgus. J Appl Biomech. 2019;35(1):44–51, https://doi.org/10.1123/jab.2017-0319, an author name was spelled incorrectly. Koichi Shinkoda was spelled Koichi Shinakoda. The online version of this article has been corrected.
Observable scapular dyskinesis is associated with biomechanical deficits. Preventative interventions aimed at correcting these deficits may aid in preventing the development and resolution of shoulder pain. Our purpose was to investigate the effects of kinesio taping (KT) on common biomechanical deficits associated with scapular dyskinesis and shoulder pain. Participants (n = 51) with observable scapular dyskinesis, and without shoulder pain were randomized to KT, KT-placebo, or a no-treatment control group. Measurements taken before, immediately after taping, and 3 days later included pectoralis minor muscle length, lower trapezius muscle strength, scapular upward rotation angle at 0° to 120° in scapular plane humeral elevation and acromiohumeral distance. There were no changes in scapular upward rotation, lower trapezius strength, and acromiohumeral distance immediately after taping or 3 days later compared to baseline (P > .05). The pectoralis minor increased in length in the KT group on day 3 compared to directly after taping (P = .03), but no difference between groups or interaction between time and group were determined (P > .05). Scapular dyskinesis prevalence did not change over time in any group (P > .05). In people with scapular dyskinesis free from shoulder pain, KT applied to the shoulder cannot be recommended to ameliorate the biomechanical deficits associated with shoulder pain.