Objective: This study aimed to investigate how knee extensor and flexor strength change over time after anterior cruciate ligament reconstruction (ACLR).
Design: Systematic review with longitudinal meta-analysis.
Data Sources: Medline, Embase, CINAHL, Scopus, Cochrane CENTRAL and SPORTDiscus to 28 February 2023.
Eligibility Criteria: Studies of primary ACLR (n≥50), with mean participant age 18-40 years, reporting a quantitative measure of knee extensor or flexor strength were eligible. Muscle strength had to be reported for the ACL limb and compared with: (1) the contralateral limb (within-person); and/or (2) an uninjured control limb (between-person).
Results: We included 232 studies of 34 220 participants. Knee extensor and flexor strength showed sharp initial improvement postoperatively before tailing off at approximately 12-18 months post surgery with minimal change thereafter. Knee extensor strength was reduced by more than 10% compared with the contralateral limb and approximately 20% compared with uninjured controls at 1 year for slow concentric, fast concentric and isometric contractions. Knee flexor strength showed smaller deficits but was still 5%-7% lower than the contralateral limb at 1 year for slow concentric, fast concentric and isometric contractions. Between-person comparisons showed larger deficits than within-person comparisons.
Conclusion: Knee extensor muscle strength is meaningfully reduced (>10%) at 1 year, with limited improvement after this time up to and beyond 5 years post surgery. Many people likely experience persistent and potentially long-term strength deficits after ACLR. Comparison within person (to the contralateral limb) likely underestimates strength deficits in contrast to uninjured controls.
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http://dx.doi.org/10.1136/bjsports-2023-107977 | DOI Listing |
Nutrients
December 2024
Department of Physical Education and Sport Science, School of Physical Education, Sport Science and Occupational Therapy, Democritus University of Thrace, 69100 Komotini, Greece.
Background/objectives: Despite being widely promoted, protein supplementation's overall effectiveness during demanding basketball schedules remains unclear. This study investigated whether increased protein intake can accelerate recovery of muscle function during a 6-day congested basketball microcycle consisting of three consecutive games while accounting for the impact of playing time.
Methods: In a randomized, two-trial, cross-over, double-blind repeated measures design, eighteen male basketball players were assigned to a high (High PT) or a moderate (Mod PT) playing time group and participated in two trials, receiving daily either milk protein (PRO trial) or an isoenergetic amount of carbohydrates.
J Physiol
January 2025
Department of Biomedical Sciences, University of Padova, Padova, Italy.
Short-term unloading experienced following injury or hospitalisation induces muscle atrophy and weakness. The effects of exercise following unloading have been scarcely investigated. We investigated the functional and molecular adaptations to a resistance training (RT) programme following short-term unloading.
View Article and Find Full Text PDFZ Orthop Unfall
January 2025
Institute of Cardiology and Sports Medicine, Department II: Molecular and Cellular Sports Medicine, German Sport University Cologne, Cologne, Germany.
Patients with knee osteoarthritis (KOA) often have impaired muscle function of the weight-bearing muscles, particularly in the knee and hip joints. This can lead to a significant loss of strength and power and may play a role in the perceived instability of the knee joint. The purpose of this study was to compare the maximum isometric strength of the hip abductor and knee extensor muscles between patients with KOA with and without perceived instability.
View Article and Find Full Text PDFJ ISAKOS
January 2025
Laboratory Study of Movement, Instituto de Ortopedia e Traumatologia do Hospital das Clínicas (IOT-HC), Faculdade de Medicina, Universidade de São Paulo (FMSUP), São Paulo, SP; Brazil.
Introduction: Chondromalacia patella (CMP) is characterized by cartilage degeneration, affects young adults, more women (2:1) and is responsible for 75% of knee pain complaints in the active population. The etiology is multifactorial and may be related to extrinsic factors (trauma and burden) and intrinsic factors (patellar malalignment and quadriceps weakness). Isokinetic dynamometry (ID) can aid in the detection of the causal factors of knee pain related to CMP.
View Article and Find Full Text PDFJ Crohns Colitis
January 2025
Professor of Gastroenterology, Translational Medical Sciences, School of Medicine, Faculty of Medicine and Health Sciences, University of Nottingham; NIHR Nottingham Biomedical Research Centre, Nottingham.
Background & Objective: IBD fatigue aetiology is poorly understood. This study quantified body composition and physical function alongside proton magnetic resonance imaging (1H MRI) and spectroscopy (31P MRS) measures of organ structure and function in quiescent Crohn's Disease patients (CD) and healthy volunteers (HV), to identify a physiological basis for IBD fatigue.
Methods: Body composition was determined using DEXA and 1H MRI.
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