Lower limb muscle and joint forces during front and back squats performed on a smith machine

2020 ◽  
pp. 1-11
Author(s):  
Rodrigo Bini ◽  
Megan Lock ◽  
Gedd Hommelhoff
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
External Load ◽  
Compressive Force ◽  
Gluteus Medius ◽  
Body Motion ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Back Squat ◽  
Joint Forces

BACKGROUND: Comparison of knee loads on a Smith machine, which utilised in for maintenance of health and rehabilitation, has not been attempted. OBJECTIVE: This study compared lower limb muscle and knee joint forces during front and back squats performed on a Smith Machine. METHODS: Eleven participants performed front and back squats with loads at 40%, 60% and 80% of their back squat 1-RMs. Ground reaction forces and three-dimensional full body motion were collected and used for modelling lower limb muscle and knee joint forces. RESULTS: Larger loads increased tibiofemoral compressive force during back squat at 80% compared to 40% (p< 0.01; d= 1.58) and to 60% (p< 0.01; d= 1.37). Patellofemoral compressive (p= 0.96) and tibiofemoral shear forces (p= 0.55) were not influenced by external load or type of squat. Gluteus medius and minimus produced more force at 80% compared to 60% (p= 0.01; d= 1.10) and to 40% (p< 0.01; d= 1.87) without differences for other muscles (p= 0.09–0.91). CONCLUSIONS: Greater external load was associated with increase in gluteus medius and minimus force and with increased tibiofemoral compressive force without effects on tibiofemoral shear force, patellofemoral compressive force or other lower limb muscle forces.

Swing Phase Mechanics of Maximal Velocity Sprints—Does Isokinetic Lower-Limb Muscle Strength Matter?

2020 ◽  
pp. 1-11
Author(s):  
Tobias Alt ◽  
Igor Komnik ◽  
Jannik Severin ◽  
Yannick T. Nodler ◽  
Rita Benker ◽  
...  
Keyword(s):  
Knee Joint ◽  
Equilibrium Point ◽  
Hip Joint ◽  
Lower Limb ◽  
Dynamic Control ◽  
Swing Phase ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Joint Mechanics ◽  
Sprint Velocity

Purpose: Concentric hip and eccentric knee joint mechanics affect sprint performance. Although the biarticular hamstrings combine these capacities, empirical links between swing phase mechanics and corresponding isokinetic outcome parameters are deficient. This explorative study aimed (1) to explain the variance of sprint velocity, (2) to compare maximal sprints with isokinetic tests, (3) to associate swing phase mechanics with isokinetic parameters, and (4) to quantify the relation between knee and hip joint swing phase mechanics. Methods: A total of 22 sprinters (age = 22 y, height = 1.81 m, weight = 77 kg) performed sprints and eccentric knee flexor and concentric knee extensor tests. All exercises were captured by 10 (sprints) and 4 (isokinetics) cameras. Lower-limb muscle balance was assessed by the dynamic control ratio at the equilibrium point. Results: The sprint velocity (9.79 [0.49] m/s) was best predicted by the maximal knee extension velocity, hip mean power (both swing phase parameters), and isokinetic peak moment of concentric quadriceps exercise (R2 = 60%). The moment of the dynamic control ratio at the equilibrium point (R2 = 39%) was the isokinetic parameter with the highest predictive power itself. Knee and hip joint mechanics affected each other during sprinting. They were significantly associated with isokinetic parameters of eccentric hamstring tests, as well as moments and angles of the dynamic control ratio at the equilibrium point, but restrictedly with concentric quadriceps exercise. The maximal sprints imposed considerably higher loads than isokinetic tests (eg, 13-fold eccentric knee joint peak power). Conclusions: Fast sprinters demonstrated distinctive knee and hip mechanics in the late swing phase, as well as strong eccentric hamstrings, with a clear association to the musculoarticular requirements of the swing phase in sprinting. The transferability of isokinetic knee strength data to sprinting is limited inter alia due to different hip joint configurations. However, isokinetic tests quantify specific sprint-related muscular prerequisites and constitute a useful diagnostic tool due to their predicting value to sprint performance.

scholarly journals Stroke Sarcopenia Patients Cause Weakness and Atrophy in the Knee and Ankle Joints

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 214-214
Author(s):  
Yamanoi Jyunya
Keyword(s):  
Knee Joint ◽  
Ankle Joint ◽  
Muscle Weakness ◽  
Muscle Atrophy ◽  
Lower Limb ◽  
Chronic Stroke ◽  
Triceps Surae ◽  
Stroke Survivors ◽  
Lower Limb Muscle ◽  
Limb Muscle

Abstract Objectives Chronic stroke survivors tend to be inactive, often with sarcopenia, and have decreased physical function and activities of daily living. Muscle atrophy and weakness differ between sarcopenia patients and stroke patients. Therefore, it is difficult to evaluate physiotherapy and intervention for sarcopenic patients with stroke. The purpose of this study was to identify muscles that cause muscle weakness and muscle atrophy in stroke sarcopenia patients. Methods The subjects were 117 chronic stroke survivors who were 65 years or older. Subjects were determined using the criteria of the Asian Working Group on Sarcopenia in 2019 to determine the presence of sarcopenia and were classified into sarcopenia group (SG, n = 60) and non sarcopenia group (nSG, n = 57). Atrophy assessments obtained unaffected lower limb muscle thickness (iliopsoas, gluteus maximus, gluteus medius, hamstrings, quadriceps femoris, tibialis anterior, triceps surae) using B-mode of transverse ultrasound imaging. Strength assessments obtained unaffected lower limb muscle strength (flexion, extension, abduction, adduction, external rotation and internal rotation of hip joint, flexion and extension of knee joint, planter flexion and dorsiflexion of ankle joint) using handheld dynamometer. We conducted a Student's t-test to compare the two groups. A P-value of &lt;0.05 was considered to show statistical significance for all analyses. When the significance level is less than 0.05, the power is also calculated, and it is considered that the significant difference can be secured when P &lt; 0.05 and power &gt;0.8. We conducted with the approval of the ethics committee of Aichi Saiseikai Rehabilitation Hospital (201,908). Results SG had muscle atrophy in all muscles compared to nSG (P &lt; 0.05, power &gt;0.8). SG had muscle weakness in all joint direction compared to nSG (P &lt; 0.05, power &gt;0.8). In particular, extension of knee joint and planter flexion of ankle joint muscle weakness, quadriceps femoris and triceps surae muscle atrophy occurred (P &lt; 0.01, power &gt;0.8). Conclusions Assessment and intervention of skeletal muscle in stroke sarcopenia patients should focus on the knee joint and ankle joint. Funding Sources The authors declare no conflicts of interest associated with this manuscript.

scholarly journals The Relationship of Lower Limb Muscle Strength and Knee Joint Hyperextension during the Stance Phase of Gait in Hemiparetic Stroke Patients

2011 ◽  
Vol 17 (3) ◽  
pp. 150-156 ◽  
Author(s):  
Allison Cooper ◽  
Ghalib Abdulllah Alghamdi ◽  
Mohammed Abdulrahman Alghamdi ◽  
Abdulrahman Altowaijri ◽  
Susan Richardson
Keyword(s):  
Muscle Strength ◽  
Knee Joint ◽  
Lower Limb ◽  
Stance Phase ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Stroke Patients ◽  
Hemiparetic Stroke ◽  
Relationship Of ◽  
The Relationship

4 Case Reports On Patients with Acute Lower Limb Muscle Weakness Treated by Spinal Mobilization With Leg Movement(SMWLM) Combined with Korean Medicine Treatment

2020 ◽  
Vol 15 (2) ◽  
pp. 63-73
Author(s):  
Young-Joo Moon ◽  
Won-Bin Shin ◽  
Gwang-Hyun Ryu ◽  
Ji-Yun Lee ◽  
Hyun-A Jeon ◽  
...  
Keyword(s):  
Muscle Weakness ◽  
Lower Limb ◽  
Case Reports ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Korean Medicine ◽  
Leg Movement
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