Lower-Limb Muscle Activity During Aquatic Treadmill Running in Individuals With Anterior Cruciate Ligament Reconstruction

Chun Lung So (Corresponding Author), Man Ying Kwok, Yin Leuk Chan, Hing Fung Kevin Lam, Hei Tung Hilda Chang, Tsz Kit Chan, Chi Yin Ken Leung , Hon Ting Tse

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


Introduction: While anterior cruciate ligament (ACL) tears are commonly managed with ACL reconstruction (ACL-R), 35% of ACL-R individuals fail to return to the preinjury elite sport level. Persistent neuromuscular deficits in the hamstrings and quadriceps have been observed. It has been proposed that aquatic therapy can be used to optimize neuromuscular control after ACL-R. Objectives: (1) To compare muscle activity in ACL-R individuals during aquatic treadmill (ATM) running at different water depths and (2) to compare muscle activity during ATM running between ACL-R and healthy individuals. Methods: A total of 38 participants, including 18 ACL-R individuals (mean postoperative time [SD] = 25.8 [25.0] mo) and 20 healthy individuals were recruited. Muscle activity of biceps femoris (BF), rectus femoris (RF), tibialis anterior, and medial gastrocnemius during land treadmill and ATM running at mid-shin, mid-thigh, and waist levels were recorded using surface electromyography (sEMG). The sEMG signals of the selected muscles were normalized and expressed in % Maximal Voluntary Contraction (%MVC). Muscle activity of the ACL-R, ACL-contralateral, and healthy control limbs at different water depths was compared. Results: Among the 3 groups, the ACL-R group demonstrated the most prominent percentage increase of 101.97% (P = .001) at mid-shin level, 139.66% (P = .001) at mid-thigh level, and 141.97% (P < .001) at waist level, respectively, in %MVC when compared to land. In the ACL-R group, muscle activity of BF in the stance phase (BFSt) was significantly higher than the control group on land at all water depths. Muscle activity of RF in the swing phase (RFSw) in the ACL-R group significantly increased in all water depths immersion when compared to land, respectively. Conclusion: This study showed an increasing trend in muscle activity of BFSt and RFSw in ACL-R individuals during ATM running at increased water depths. ATM running could be implemented as neuromuscular training in rehabilitation after ACL-R.
Original languageEnglish
Article number10.1123/jsr.2021-0431
Pages (from-to)894-903
Number of pages10
JournalJournal of Sport Rehabilitation
Issue number7
Publication statusPublished - 29 Apr 2022


  • electromyography
  • muscle activation
  • neuromuscular training

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation


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