14 research outputs found
Influence of increasing knee flexion angle on knee-ankle varus stress during single-leg jump landing
Objectives: The primary aim of this study was to identify the relationship between the peak knee flexion angle and knee-ankle varus stress in the landing phase of the single-leg jump during running. Methods: Fifteen male handball players from the first Saudi Arabian handball team were incorporated in this study. Each player performed a single-leg jump-land after running a fixed distance of 450 cm. The data were measured using a 3D motion analysis system. The maximum knee flexion angle, knee varus angle, centre of pressure pathway in the medio-lateral direction, and ankle varus moment were measured. Results: The Pearson Product Moment Correlation showed that a greater knee flexion angle was related to a greater lateral displacement of the centre of pressure (r = 0.794, P = 0.000), a greater ankle varus moment (r = 0.707, P = 0.003), and a greater knee varus angle (r = 0.753, P = 0.001). In addition, the greater ankle varus moment was related to the greater lateral displacement of the centre of pressure (r = 0.734, P = 0.002). Conclusions: These findings may help physical therapists and conditioning professionals to understand the impact of increasing knee flexion angle on the lower limb joints. Such findings may help to develop training protocols for enhancing the lateral body reaction during the landing phase of the single-leg jump, which may protect the knee and ankle joints from excessive varus stresses. Keywords: 3D motion analysis, Ankle kinetic, Centre of pressure pathway, Handball playing, Knee kinematic, Single-leg jum
Effects of Neuromuscular Fatigue on Eccentric Strength and Electromechanical Delay of the Knee Flexors
Purpose: To examine the effects of fatiguing isometric contractions on maximal eccentric strength and electromechanical delay (EMD) of the knee flexors in healthy young adults of different training status.
Methods: Seventy-five male participants (27.7 ± 5.0 years) were enrolled in this study and allocated to three experimental groups according to their training status: athletes (ATH, n = 25), physically active adults (ACT, n = 25), and sedentary participants (SED, n = 25). The fatigue protocol comprised intermittent isometric knee flexions (6-s contraction, 4-s rest) at 60% of the maximum voluntary contraction until failure. Pre- and post-fatigue, maximal eccentric knee flexor strength and EMDs of the biceps femoris, semimembranosus, and semitendinosus muscles were assessed during maximal eccentric knee flexor actions at 60, 180, and 300°/s angular velocity. An analysis of covariance was computed with baseline (unfatigued) data included as a covariate.
Results: Significant and large-sized main effects of group (p ≤ 0.017, 0.87 ≤ d ≤ 3.69) and/or angular velocity (p < 0.001, d = 1.81) were observed. Post hoc tests indicated that regardless of angular velocity, maximal eccentric knee flexor strength was lower and EMD was longer in SED compared with ATH and ACT (p ≤ 0.025, 0.76 ≤ d ≤ 1.82) and in ACT compared with ATH (p = ≤0.025, 0.76 ≤ d ≤ 1.82). Additionally, EMD at post-test was significantly longer at 300°/s compared with 60 and 180°/s (p < 0.001, 2.95 ≤ d ≤ 4.64) and at 180°/s compared with 60°/s (p < 0.001, d = 2.56), irrespective of training status.
Conclusion: The main outcomes revealed significantly higher maximal eccentric strength and shorter eccentric EMDs of knee flexors in individuals with higher training status (i.e., athletes) following fatiguing exercises. Therefore, higher training status is associated with better neuromuscular functioning (i.e., strength, EMD) of the hamstring muscles in fatigued condition. Future longitudinal studies are needed to substantiate the clinical relevance of these findings
Effects of Neuromuscular Fatigue on Eccentric Strength and Electromechanical Delay of the Knee Flexors
Purpose: To examine the effects of fatiguing isometric contractions on maximal eccentric strength and electromechanical delay (EMD) of the knee flexors in healthy young adults of different training status.
Methods: Seventy-five male participants (27.7 ± 5.0 years) were enrolled in this study and allocated to three experimental groups according to their training status: athletes (ATH, n = 25), physically active adults (ACT, n = 25), and sedentary participants (SED, n = 25). The fatigue protocol comprised intermittent isometric knee flexions (6-s contraction, 4-s rest) at 60% of the maximum voluntary contraction until failure. Pre- and post-fatigue, maximal eccentric knee flexor strength and EMDs of the biceps femoris, semimembranosus, and semitendinosus muscles were assessed during maximal eccentric knee flexor actions at 60, 180, and 300°/s angular velocity. An analysis of covariance was computed with baseline (unfatigued) data included as a covariate.
Results: Significant and large-sized main effects of group (p ≤ 0.017, 0.87 ≤ d ≤ 3.69) and/or angular velocity (p < 0.001, d = 1.81) were observed. Post hoc tests indicated that regardless of angular velocity, maximal eccentric knee flexor strength was lower and EMD was longer in SED compared with ATH and ACT (p ≤ 0.025, 0.76 ≤ d ≤ 1.82) and in ACT compared with ATH (p = ≤0.025, 0.76 ≤ d ≤ 1.82). Additionally, EMD at post-test was significantly longer at 300°/s compared with 60 and 180°/s (p < 0.001, 2.95 ≤ d ≤ 4.64) and at 180°/s compared with 60°/s (p < 0.001, d = 2.56), irrespective of training status.
Conclusion: The main outcomes revealed significantly higher maximal eccentric strength and shorter eccentric EMDs of knee flexors in individuals with higher training status (i.e., athletes) following fatiguing exercises. Therefore, higher training status is associated with better neuromuscular functioning (i.e., strength, EMD) of the hamstring muscles in fatigued condition. Future longitudinal studies are needed to substantiate the clinical relevance of these findings
The effectiveness of the Copenhagen adduction exercise on improving eccentric hip adduction strength among soccer players with groin injury: a randomized controlled trial
Groin injuries are common in soccer players and often involve adductor muscle strains. The Copenhagen Adduction Exercise (CAE) is a targeted intervention whose effectiveness in rehabilitation for these injuries warrants investigation. To investigate the impact of a rehabilitation program, which includes the CAE, on eccentric hip adduction (EHAD) strength, hip joint range of motion (ROM), self-reported disability, and pain among soccer players with adductor-related groin pain. It was hypothesized that the addition of CAE to the rehabilitation program would yield greater improvements. Employing a randomized controlled trial with a two-group parallel design, thirty male soccer players with a mean age of 26.4 ± 3.9 years were randomized into an intervention group (IG) including CAE (n = 15) and a control group (CG) without CAE (n = 15), based on a power analysis to ensure 80% power to detect significant differences. Both groups engaged in their respective rehabilitation programs twice a week for eight weeks. The primary outcome measured was EHAD strength, while secondary outcomes included hip joint ROM, self-reported disability measured by the Copenhagen Hip and Groin Outcome Score (HAGOS), and pain levels. Significant improvements within groups were observed across all measures (p Incorporating the CAE into rehabilitation programs significantly improves EHAD strength, decreases pain scores, and reduces self-reported disability in soccer players with adductor-related groin pain. ClinicalTrials.gov identifier: NCT05589623</p
Corridor and real-time 6-minute walk tests in healthy young adults: A randomized cross-over study
الملخص: أهداف البحث: التحمل القلبي الرئوي مهم للمشاركة بشكل مريح في أنشطة الحياة اليومية. تستخدم اختبارات التمرين، مثل اختبار المشي لمدة ست دقائق، بشكل شائع لتقييم القدرة على التحمل القلبي الرئوي. نحن نهدف إلى دراسة تأثيرات اختبار المشي لمدة ست دقائق القائم على الممر والمعتمد على مختبر تحليل المشية في الوقت الحقيقي التفاعلي على الأداء الوظيفي. طريقة البحث: تم تقسيم ثلاثين رجلا أصحاء بشكل عشوائي إلى مجموعتين. أجرى المشاركون في المجموعة (أ) اختبار المشي لمدة ست دقائق على الممر، تليها فترة الراحة (ساعة واحدة)، وبعد ذلك، قاموا بإجراء اختبار المشي في الوقت الحقيقي للتحليل التفاعلي القائم على المشي لمدة ست دقائق. في المجموعة (ب)، أجرى المشاركون الاختبارات بتسلسل عكسي لتلك التي أجراها المشاركون في المجموعة (أ). النتائج: أدى اختبار المشي لمدة ست دقائق القائم على الممر إلى زيادة كبيرة في مسافة ست دقائق سيرا على الأقدام (6 ميجاوات) وسرعة المشي لمدة ست دقائق مقارنة باختبار المشي لمدة ست دقائق القائم على مختبر التحليل التفاعلي في الوقت الحقيقي. لم يلاحظ أي فروق ذات دلالة إحصائية بين المجموعتين في أي من النتائج الثانوية التالية: ضغط الدم الانقباضي، وضغط الدم الانبساطي، وتشبع الأكسجين، ومعدل ضربات القلب، وضيق التنفس، والتعب العام. ولوحظ وجود علاقة إيجابية قوية بين مسافة اختبار المشي البالغة ست دقائق وسرعة اختبار المشي لمدة ست دقائق. الاستنتاجات: لا ينبغي استخدام اختبار المشي لمدة ست دقائق القائم على الممر واختبار المشي في الوقت الحقيقي للتحليل التفاعلي القائم على المختبر لمدة ست دقائق بشكل تبادلي. Abstract: Objective: Cardiopulmonary endurance is important for comfortably participating in activities of daily living. Exercise tests, such as the 6-minute walk test (6MWT), are commonly used to evaluate cardiopulmonary endurance. We investigated the effects of the Gait Real-Time Analysis Interactive Lab (GRAIL)- and corridor-based 6MWTs on functional performance. Methods: Thirty healthy men were randomly divided into two groups. Group A participants performed a corridor-based 6MWT, followed by a washout period (1 h). Subsequently, they performed the GRAIL-based 6MWT. Group B participants performed the tests in the reverse order of that performed by Group A participants. Results: The corridor-based 6MWT resulted in significantly higher 6MW distance and 6MW speed than the GRAIL-based 6MWT. No significant differences were observed between the two groups in any of the following secondary outcomes: systolic blood pressure, diastolic blood pressure, oxygen saturation, heart rate, dyspnea, and overall fatigue. A strong positive correlation was observed between the 6MW distance and 6MW speed. Conclusion: The corridor- and GRAIL-based 6MWT should not be used interchangeably