Influence of Isokinetic Knee Muscle Torque at Different Angular Velocities on Standing Posture Stability in Healthy Adults

2018 ◽  
Vol 28 (02) ◽  
pp. 129-134
Author(s):  
Sami Al-Abdulwahab ◽  
Shaji Kachanathu ◽  
Faris Alodaibi

Abstract Objectives Knee muscle groups contribute to proper and safe static and dynamic standing posture stability. The impact of isokinetic knee muscle torque at various angular velocities on standing posture stability is poorly understood. We investigated the influence of isokinetic knee muscle torque at different angular velocities on standing posture stability. Design Cross-sectional study. Setting King Saud University Campus labs. Method The study population was a convenience sample of 30 healthy volunteer college students with a mean age of 20±2 years. Isokinetic concentric peak torque (PT) of knee extensor (Q) and flexor (H) muscle groups as well as the flexor to extensor (H:Q) ratio at three different angular velocities: (60, 180, and 300°/s) were measured, respectively. The postural stability was also measured in both static and dynamic components. The Pearson correlation coefficient was used to examine the association between the different isokinetic components and postural stability (both static and dynamic). Results The PT of Q and H muscle groups and the H:Q ratio at the 3 different angular velocities were significantly associated with static standing balance with eye open on a firm surface (p<0.033). Moreover, the PT of Q at 60 and 180°/s angular velocities was significantly associated with maximum and endpoint excursion components of dynamic standing balance (p<0.044). Conclusions The PT of both Q and H muscle groups at different angular velocities are associated with maintenance of standing static balance. PT of Q only is significantly associated with control of dynamic standing balance in the lower angular velocities.

Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.


2008 ◽  
Vol 28 (1) ◽  
pp. 58-61 ◽  
Author(s):  
Christopher T. Ray ◽  
Michael Horvat ◽  
Ronald Croce ◽  
R. Christopher Mason ◽  
Steven L. Wolf

2021 ◽  
Vol 61 ◽  
pp. 102608
Author(s):  
Munlika Sremakaew ◽  
Julia Treleaven ◽  
Gwendolen Jull ◽  
Parinya Vongvaivanichakul ◽  
Sureeporn Uthaikhup

2018 ◽  
Vol 32 (2) ◽  
pp. 166-174 ◽  
Author(s):  
Esther M. J. Bekkers ◽  
Kim Dockx ◽  
Surendar Devan ◽  
Sam Van Rossom ◽  
Sabine M. P. Verschueren ◽  
...  

2018 ◽  
Vol 39 (09) ◽  
pp. 688-695 ◽  
Author(s):  
Joao Duarte ◽  
João Valente-dos-Santos ◽  
Manuel Coelho-e-Silva ◽  
R. Malina ◽  
Dieter Deprez ◽  
...  

AbstractThis study aimed to examine longitudinal changes in isometric strength of the knee extensors (ImKE) and knee flexors (ImKF) at 30° and 60°. The sample was composed of 67 players aged 11.0–13.9 years at baseline over five years. Stature, body mass, skinfolds, and isometric strength (ImKE30°, ImKF30°, ImKE60° and ImKF60°) were measured. Fat mass and fat-free mass (FFM) were derived from skinfolds. Skeletal age was obtained using TW2 RUS. Multilevel random effects regression analyses extracted developmental polynomial models. An annual increment on chronological age (CA) corresponded to 5.6 N (ImKE30°), 2.7 N (ImKF30°), 4.6 N (ImKE60°) and 1.5 N (ImKF60°). An increment of 1 kg in FFM predicted isometric strength as follows: 1.2 N (ImKE30°), 2.1 N (ImKF30°), 3.1 N (ImKE60°) and 2.0 N (ImKF60°). The following equations were obtained: ImKE30°=5.759×CA+1.163×FFM; ImKF30°=−19.369+2.691×CA+0.693×CA2+2.108×FFM; ImKE60°=4.553×CA+3.134×FFM; and, ImKF60°=-19.669+1.544×CA+2.033×FFM. Although skeletal maturity had a negligible effect on dependent variables, age and body size, based on FFM, were relevant longitudinal predictors. During adolescence, systematic assessment of knee extensors and knee flexors are strongly recommended to prevent impairment of knee muscle groups.


Author(s):  
Bożena Wojciechowska-Maszkowska ◽  
Dorota Borzucka

The aim of this study was to evaluate the effect of additional load on postural-stability control in young women. To evaluate postural control in the 34 women in this study (mean age, 20.8 years), we measured postural sway (center of pressure, COP) in a neutral stance (with eyes open) in three trials of 30 s each. Three load conditions were used in the study: 0, 14, and 30 kg. In analysis, we used three COP parameters, variability (linear), mean sway velocity (linear), and entropy (nonlinear). Results suggested that a considerable load on a young woman’s body (approximately 48% of body weight) had significant influence on stability. Specifically, heavy loads triggered random movements, increased the dynamics of postural-stability control, and required more attention to control standing posture. The results of our study indicate that inferior postural control mainly results from insufficient experience in lifting such a load.


2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Jin Hyuck Lee ◽  
Dae-Hee Lee ◽  
Jong-Hoon Park ◽  
Dong Won Suh ◽  
Eunseon Kim ◽  
...  

Abstract Background Only limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups. Methods Ninety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior–posterior stability index (APSI), and medial–lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device. Results In the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05). Conclusion Dynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear. Level of evidence: Level III


2020 ◽  
Vol 9 (5) ◽  
pp. 1554 ◽  
Author(s):  
Rula Abdallat ◽  
Feras Sharouf ◽  
Kate Button ◽  
Mohammad Al-Amri

Dual-task paradigms have been increasingly used to assess the interaction between cognitive demands and the control of balance and gait. The interaction between functional and cognitive demands can alter movement patterns and increase knee instability in individuals with knee conditions, such as knee anterior cruciate ligament (ACL) injury or osteoarthritis (OA). However, there is no consensus on the effects of dual-task on gait mechanics and balance in those individuals. This systematic scoping review aims to examine the impact of dual-task gait and standing balance on motor and cognitive performance in individuals with knee OA or ACL injury. A comprehensive search of MEDLINE, PubMed, Web of Science, and EMBASE electronic databases up until December 2019 was carried out. Inclusion criteria was limited to include dual-task studies that combined cognitive tasks performed simultaneously with gait or standing balance in individuals with knee OA or ACL injuries. In total, fifteen studies met the inclusion criteria, nine articles examined dual-task effects on balance, and six articles reported the effects of dual-task on gait. The total number of individuals included was 230 individuals with ACL injuries, and 168 individuals with knee OA. A decline in gait and balance performance during dual-task testing is present among individuals with ACL injury and/or ACL reconstruction and knee OA. Further research is required, but dual taking assessment could potentially be used to identify individuals at risk of falling or further injury and could be used to develop targeted rehabilitation protocols. A variety of outcome measures have been used across the studies included, making comparisons difficult. The authors, therefore, recommend developing a standardized set of biomechanical balance variables.


Author(s):  
Louay S. Yousuf ◽  
Anis Drira

In this paper, a polydyne cam with translated roller follower over a range of speeds are analyzed. There is a clearance between the follower and the guide. The dynamic simulation is investigated taking into account the impact and the friction. The simulation has been done by using Solidworks program. The effect of follower guides’ clearances on roller follower non-periodicity is considered based on Lyapunov exponent technique. Rosenstein method is used to calculate largest Lyapunov exponent for different angular velocities of the cam. The experimental setup has been implemented by using OPTOTRAK/3020 through a 3-D infrared markers to track follower motion. The power spectrum analysis of Fast Fourier Transform and phase plane contour are examined roller follower non-periodicity.


Sign in / Sign up

Export Citation Format

Share Document