biceps femoris

Background: A common musculoskeletal issue that can affect dynamic knee stability, balance functional performance and quality of life is chronic knee pain. Exercise therapy is a first-line treatment, but it’s unclear if Biceps Femoris-focused eccentric exercise has any additional benefits. Objective: To compare the effects of Biceps Femoris–focused eccentric exercise and regular physiotherapy on dynamic knee stability and pain in patients with chronic knee pain. Methods: This was a parallel group, single-blinded, randomized controlled trial conducted in the outpatient physiotherapy department of JPMC, BAWS Health Facility, Karachi, Pakistan, from 01 March 2026 to 31 August 2026. A total of 160 participants with chronic knee pain were randomly assigned to either the Biceps Femoris–focused eccentric exercise group (n = 80) or the standard physiotherapy exercise group (n = 80). For 6 weeks, both groups underwent 3 sessions of supervised exercise therapy three times per week for six weeks (18 sessions total). Progressive eccentric hamstring exercises emphasizing eccentric knee flexion, external tibial rotation and single-leg control were performed by the Biceps Femoris-focused eccentric exercise group. These exercises included Romanian deadlifts, lateral step-downs with external rotation cueing, prone knee curls with external tibial rotation, side-lying hip extension with knee flexed 30-45°, standing hip hinges with band resistance, single-leg squats to a box. Straight leg raises, mini-squats (0–45°), step-ups, terminal knee extension with band, static hamstring and calf stretches, and single-leg stance balance training were among the traditional knee rehabilitation exercises performed by the standard physiotherapy group. A total of 149 participants finished the study and were included in the final analysis (74 in the Biceps Femoris–focused eccentric exercise group and 75 in the standard physiotherapy group). The primary outcomes were dynamic knee stability which was assessed using the Star Excursion Balance Test, and pain intensity was assessed by using the Numerical Pain Rating Scale. Secondary outcomes were functional performance, knee-related disability, and adverse events. Data were analyzed using SPSS version 26.0, with statistical significance set at p < 0.05. Results: Dynamic knee stability, pain, functional performance and knee related disability all improved in both groups after six weeks. But compared to the standard physiotherapy group, the Biceps Femoris-focused eccentric exercise group significantly improved dynamic knee stability (mean change: 8.4 ± 3.1 vs. 3.6 ± 2.7; mean difference: 4.8; 95% CI: 3.9 to 5.7; p < 0.001). Additionally, the eccentric exercise group experienced a significantly higher reduction in pain (mean change: 3.3 ± 1.2 vs. 2.1 ± 1.3; mean difference: 1.2; 95% CI: 0.8 to 1.6; p < 0.001). Functional performance and knee related disability improved more in eccentric exercise group. The most frequent adverse event was mild muscle soreness; no significant adverse events were noted. Conclusion: For patients with chronic knee pain, Biceps Femoris-focused eccentric exercise was more beneficial than conventional physiotherapy in terms of enhancing dynamic knee stability and lowering pain. It might be suggested as a practical and safe supplement to conventional physiotherapy rehabilitation.

matched text: “biceps femoris”

I read with great interest the recent article by Natsios et al., “The role of muscle forces on rotational and cranio-caudal stability in the intact and CCL-deficient stifle: An ex vivo biomechanical study.”1 The authors used a cable-actuated cadaveric model capable of graded, multi-muscle activation. This is a meaningful advance over the fixed-tension surrogates used in earlier work. Periarticular muscle cocontraction nearly normalized internal tibial rotation in the cranial cruciate ligament (CCL)-deficient stifle, while cranio-caudal translation remained markedly elevated. The clinical implications, particularly regarding targeted biceps femoris strengthening, are appropriately emphasized. I would like to raise two points that may warrant clarification. First, each specimen underwent the full activation matrix—eight muscle conditions × seven activation levels, with triplicate repetitions for cranio-caudal translation testing—while intact. Only afterward was the CCL transected and the same matrix repeated on the same joint. Randomizing CCL status is clearly not feasible once the ligament is transected. However, no preconditioning protocol is reported to stabilize the viscoelastic behavior of the periarticular soft tissues before testing began. Recent systematic reviews applying validated risk-of-bias instruments to this category of cadaveric biomechanical studies report that even well-conducted investigations rarely achieve an ideal methodological quality score.2 This suggests that specimen handling and testing-protocol details are often incompletely reported in this literature. Given the substantial cumulative loading each joint underwent during the intact-condition series, accumulated creep or stress relaxation may have contributed to the reduction in internal rotation observed after transection, independent of CCL status itself. I would suggest that the authors report whether preconditioning cycles were performed, and whether cumulative loading history was assessed—for example, through a time-control condition or an analysis of drift across repeated trials. Second, I would welcome clarification of the non-significant comparison between intact and CCL-deficient internal rotation at 100% bodyweight three-muscle cocontraction (4.3° ± 2.3° vs. 2.8° ± 1.3°; p > .05). The Discussion interprets this as evidence that muscle activation restores rotational stability to near-intact levels. A non-significant p-value in a study of n = 8 does not, by itself, demonstrate equivalence. It may simply reflect limited statistical power, especially given the wide standard deviations relative to the means. Recent veterinary methodological literature has repeatedly cautioned against inferring “no difference” or “no effect” from non-significant results, and has called for effect estimates to be reported alongside confidence intervals instead.3, 4 Without such analysis, the clinical message that targeted strengthening can substantially normalize rotational laxity may overstate what the data support. I would recommend that the authors report a post hoc power calculation, or a formal equivalence analysis (e.g., two one-sided tests), for this comparison. I commend the authors for an elegant and clinically relevant experimental model. I believe these clarifications would strengthen confidence in the study's conclusions and their translation into clinical practice. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

matched text: “biceps femoris”