scholarly journals Preparatory Knee Flexion-Extension Movements Enhance Rapid Sidestepping Performance in Collegiate Basketball Players

2021 ◽  
Vol 3 ◽  
Author(s):  
Masahiro Fujimoto ◽  
Eri Uchida ◽  
Akinori Nagano ◽  
Mark W. Rogers ◽  
Tadao Isaka
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Knee Extension ◽  
Movement Initiation ◽  
Basketball Players ◽  
Step Initiation ◽  
Limb Loading ◽  
Flexion Extension ◽  
Collegiate Basketball ◽  
Lift Off

Lower-limb weight-bearing load distribution in stationary standing influences the timing of rapid first step initiation of importance for functional movement activities and agility performance in sports. This study investigated the effect of pre-step lower-limb loading and unloading with preparatory knee flexion-extension movements on sidestepping performance in fifteen male collegiate basketball players. Participants performed two-choice (step limb) reaction time sidestepping under two conditions: without preparatory movements before the go cue (no-prep–NP) and with continuous alternating knee extension and flexion movements (prep–P). The reaction signal was provided at the beginning of knee extension and flexion and during these movements which corresponded with the largest and smallest loading instants and the transition states between those instants. Sidestepping performance was assessed with three-dimensional kinematic data and ground reaction forces. Step initiation onset time was significantly faster by 13–15% than the NP condition when initiated in the knee flexion phase (p ≤ 0.028, r ≥ 0.70), whereas step-limb unloading interval from step initiation to step lift-off was significantly faster by 12–15% in the knee extension phase (p ≤ 0.01, r ≥ 0.74). The preparatory movements significantly shortened step lift-off by 10–12% (p ≤ 0.013, r ≥ 0.73) and step duration by 17–21% (p < 0.001, r ≥ 0.85) with 19–22% faster step velocity (p < 0.001, r ≥ 0.84), which resulted in 14–15% shorter overall time to step landing (p < 0.001, r ≥ 0.84), irrespective of the loading phases. These results indicated that lower-limb loading with pre-step knee flexion facilitated faster step initiation, while lower-limb unloading with knee extension facilitated faster step-limb unloading, both resulting in faster step lift-off. Bilateral knee flexion-extension movements as a preparatory action could be utilized by invasion sports players to facilitate reactive stepping performance for more effective movement initiation.

scholarly journals Reliability of a New Portable Dynamometer for Assessing Hip and Lower Limb Strength

2021 ◽  
Vol 11 (8) ◽  
pp. 3391
Author(s):  
Jan Marušič ◽  
Goran Marković ◽  
Nejc Šarabon
Keyword(s):  
Lower Limb ◽  
External Rotation ◽  
Peak Torque ◽  
Knee Extension ◽  
Lower Limb Muscles ◽  
Lower Limb Strength ◽  
Flexion Extension ◽  
Strength Tests ◽  
Hip Abduction ◽  
Maximal Peak

The purpose of this study was to evaluate intra- and inter-session reliability of the new, portable, and externally fixated dynamometer called MuscleBoard® for assessing the strength of hip and lower limb muscles. Hip abduction, adduction, flexion, extension, internal and external rotation, knee extension, ankle plantarflexion, and Nordic hamstring exercise strength were measured in three sessions (three sets of three repetitions for each test) on 24 healthy and recreationally active participants. Average and maximal value of normalized peak torque (Nm/kg) from three repetitions in each set and agonist:antagonist ratios (%) were statistically analyzed; the coefficient of variation and intra-class correlation coefficient (ICC2,k) were calculated to assess absolute and relative reliability, respectively. Overall, the results display high to excellent intra- and inter-session reliability with low to acceptable within-individual variation for average and maximal peak torques in all bilateral strength tests, while the reliability of unilateral strength tests was moderate to good. Our findings indicate that using the MuscleBoard® dynamometer can be a reliable device for assessing and monitoring bilateral and certain unilateral hip and lower limb muscle strength, while some unilateral strength tests require some refinement and more extensive familiarization.

Relationship between Hip and Knee Strength and Knee Valgus during a Single Leg Squat

2006 ◽  
Vol 22 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Tina L. Claiborne ◽  
Charles W. Armstrong ◽  
Varsha Gandhi ◽  
Danny M. Pincivero
Keyword(s):  
Knee Flexion ◽  
Frontal Plane ◽  
Peak Torque ◽  
Knee Extension ◽  
Valgus Knee ◽  
Knee Motion ◽  
Knee Strength ◽  
Flexion Extension ◽  
Hip Abduction ◽  
Single Leg Squat

The purpose of this study was to determine the relationship between hip and knee strength, and valgus knee motion during a single leg squat. Thirty healthy adults (15 men, 15 women) stood on their preferred foot, squatted to approximately 60 deg of knee flexion, and returned to the standing position. Frontal plane knee motion was evaluated using 3-D motion analysis. During Session 2, isokinetic (60 deg/sec) concentric and eccentric hip (abduction/adduction, flexion/extension, and internal/external rotation) and knee (flexion/extension) strength was evaluated. The results demonstrated that hip abduction (r2= 0.13), knee flexion (r2= 0.18), and knee extension (r2= 0.14) peak torque were significant predictors of frontal plane knee motion. Significant negative correlations showed that individuals with greater hip abduction (r= –0.37), knee flexion (r= –0.43), and knee extension (r= –0.37) peak torque exhibited less motion toward the valgus direction. Men exhibited significantly greater absolute peak torque for all motions, excluding eccentric internal rotation. When normalized to body mass, men demonstrated significantly greater strength than women for concentric hip adduction and flexion, knee flexion and extension, and eccentric hip extension. The major findings demonstrate a significant role of hip muscle strength in the control of frontal plane knee motion.

scholarly journals Soft soled footwear has limited impact on toddler gait

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251175
Author(s):  
Cylie Williams ◽  
Jessica Kolic ◽  
Wen Wu ◽  
Kade Paterson
Keyword(s):  
Knee Flexion ◽  
Subtalar Joint ◽  
Clinical Importance ◽  
Knee Extension ◽  
Temporal Data ◽  
Range Of Movement ◽  
Camera System ◽  
Peak Knee ◽  
Flexion Extension ◽  
Quasi Experimental

The development of walking in young toddlers is an important motor milestone. Walking patterns can differ widely amongst toddlers, and are characterised by unique biomechanical strategies. This makes comparisons between newly walking toddler’s and older children’s walking difficult. Little is currently understood regarding the effects of footwear on the gait in newly walking toddlers. A quasi-experimental pre-post study design was used to assess whether spatiotemporal parameters of gait, and in-shoe foot and lower limb kinematics, differed when walking barefoot and in soft-soled footwear in newly walking toddlers. There were 18 toddlers recruited, with 14 undergoing testing. The GAITRite system collected spatial and temporal data. The Vicon camera system collected kinematic data. The testing conditions included barefoot and footwear. Footwear tested was a commercially available soft soled shoe (Bobux XPLORER). Data was extracted directly from the GAITRite system and analysed. Walking in footwear did not change spatial or temporal data, however there were small but significant decreases in hip adduction/abduction range of motion (mean difference (MD) = 1.79°, 95% CI = -3.51 to -0.07, p = 0.04), knee flexion (MD = -7.63°, 95% CI = 2.70 to 12.55, p = 0.01), and knee flexion/extension range of movement (MD = 6.25°, 95% CI = -10.49 to -2.01, p = 0.01), and an increase in subtalar joint eversion (MD = 2.85°, 95% CI = 5.29 to -0.41, p = 0.03). Effect sizes were small for hip and ankle range, peak knee extension, and subtalar joint ranges (d<0.49), medium for knee flexion/extension range (d = 0.75) and large for peak knee flexion (d = 0.87). The magnitude of kinematic changes with soft-soled footwear were small thus the clinical importance of these findings is uncertain. Future longitudinal studies are needed to develop recommendations regarding footwear for newly walking toddlers.

scholarly journals Relationships between Lower Limb Loading Force and Knee Extension Strength and Ability to Maintain Sitting of Hemiplegic Patients

2010 ◽  
Vol 25 (3) ◽  
pp. 427-430
Author(s):  
Hiroshi OTAO ◽  
Shin MURATA ◽  
Jun MURATA ◽  
Syozo NAKAMURA ◽  
Akihiro MIZOKAMI ◽  
...  
Keyword(s):  
Lower Limb ◽  
Knee Extension ◽  
Knee Extension Strength ◽  
Limb Loading

Comparison of Lower Extremity Muscle Flexibility in Amateur and Trained Bharatanatyam Dancers and Nondancers

2018 ◽  
Vol 33 (1) ◽  
pp. 20-25
Author(s):  
Monica Sharma ◽  
Shibili Nuhmani ◽  
Deepti Wardhan ◽  
Qassim I Muaidi
Keyword(s):  
Internal Rotation ◽  
Lower Limb ◽  
Knee Flexion ◽  
External Rotation ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Lower Extremity Muscle ◽  
Significant Difference ◽  
Flexion Extension ◽  
Hip Flexion

OBJECTIVE: This study compared lower limb muscle flexibility between amateur and trained female Bharatanatyam dancers and nondancers. METHODS: Subjects consisted of 105 healthy female volunteers, with 70 female Bharatanatyam dancers (35 trained, 35 amateurs) and 35 controls, with a mean (±SD) age of 16.2±1.04 yrs, height 155.05±4.30 cm, and weight 54.54±2.77 kg. Participants were assessed for range of motion (ROM) in hip flexion, hip extension, hip abduction and adduction, hip external rotation, hip internal rotation, knee flexion, knee extension, ankle dorsiflexion (DF), and ankle plantar flexion (PF) by using a standardized goniometer. To assess for significant difference between groups, one-way ANOVA was applied, and multiple comparisons were made using Bonferroni correction. RESULTS: Trained dancers had a significantly greater hip flexion, extension, abduction, and external rotation ROM than amateurs and nondancers (p<0.05). Also, internal rotation and adduction were markedly less in trained dancers (p<0.05). Knee flexion, extension, and ankle DF were higher and ankle PF ROM was lesser in trained dancers. However, not much variation was found in ankle DF and PF between amateur dancers and nondancers (p>0.05). CONCLUSION: Results showed that there are significant differences in lower limb muscle flexibility between trained and amateur Bharatanatyam dancers and nondancers. These differences may be due to individual dance postures such as araimandi and muzhumandi.

scholarly journals Muscle strength evaluation of limb dominance in prepubescent swimmers boys and girls

2021 ◽  
Vol 13 (3) ◽  
pp. 23-30
Author(s):  
AYKUT OZCADIRCI ◽  
FERHAT OZTURK ◽  
SUKRU ALPAN CINEMRE ◽  
GIZEM IREM KINIKLI
Keyword(s):  
Muscle Strength ◽  
Lower Limb ◽  
Knee Flexion ◽  
T Test ◽  
Strength Ratio ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Flexion Extension ◽  
Dominant Side ◽  
Isometric Muscle

Background: The aim of this study was to compare the lower limb muscle strength in terms of gender and limb dominancy in prepubescent swimmers. Material and Methods: Seventy-four prepubescent swimmers (mean age: 11.01±1.58 years; 42 boys; 32 girls) who were training for at least 8 hours a week and without current lower limb pain participated in the study. Isometric muscle strength of lower limb was measured by hand-held dynamometry. Independent samples-t test was used to determine the difference between genders, while paired samples-t test was used for dominant-nondominant side comparison. The significance level was accepted as p<0.05. Results: Knee flexion (p<0.001), extension (p<0.001) and ankle dorsiflexion (p=0.003) muscle strength were stronger on the dominant side than on the non-dominant side. Knee flexion/extension strength ratio was similar (p=0.957); while ankle plantar flexion/dorsiflexion strength ratio was significantly different (p=0.011). Boys swimmers had stronger isometric muscle strength in the dominant side together with knee flexion (p=0.018) and knee flexion extension strength ratio (p=0.007) than girls swimmers. Conclusion: Boys swimmers had higher dominant side knee flexion muscle strength compared to female peers. Gender and lower limb dominancy might be important for lower limb muscle strength to show varieties in prepubescent swimmers before planning a training program.

scholarly journals Muscle Fatigue Assesment of the Lower Limb in Young Hurdlers Using Isokinetic Dynamometry

GYMNASIUM ◽  
2019 ◽  
Vol XIX (2) ◽  
pp. 145
Author(s):  
Gheorghe-Adrian Onea ◽  
Lorand Balint ◽  
Ștefan Alecu ◽  
Doru Oprea
Keyword(s):  
Muscle Fatigue ◽  
Lower Limb ◽  
Knee Flexion ◽  
Total Work ◽  
Isokinetic Dynamometry ◽  
Lower Limb Muscles ◽  
Flexion Extension ◽  
Hip Abduction ◽  
The Right ◽  
Work First

This research study aim was to assess muscle fatigue of the dominant and non-dominant lower limb (knee flexion/extension, hip abduction/adduction and ankle plantar/dorsoflexion), using Biodex System 4 ProTM. This investigation tested the lower limb muscles during isokinetic concentric/concentric mode at 60o /sec,120o /sec, 300o /sec,450o /sec. Hip abduction/adduction of the right and left side values range for total work from 101.6 J to 528.1 J ; work first third from 32.7 J to 164.7 J; work last third from 25.2 J to 183.7 J. Knee flexion/extension of the right and left side values range for total work from 443.2 J to 792.2 J; work first third from 135.7 J to 258.7 J; work last third from 124.1 J to 249.2 J. The present study suggests that as we change the velocity, muscle fatigue can affect the kinetic lower limb chain.

scholarly journals Different Lower-Limb Setup Positions Do Not Consistently Change Backstroke Start Time to 10 m

Sports ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 43
Author(s):  
Gordon E. Barkwell ◽  
James P. Dickey
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
High Speed ◽  
Sagittal Plane ◽  
Body Position ◽  
Knee Extension ◽  
Knee Extensors ◽  
Start Time ◽  
Performance Impact ◽  
Maximum Effort

Backstroke starts involve the athlete starting from a flexed position with their feet against the pool wall and then extending their ankles, knees, hips and back to push off; however, swimmers can start in different positions. The purpose of this study was to evaluate the performance impact of different knee extension angles in the setup position for a backstroke start. Ten backstroke swimmers completed maximum-effort starts in each of two setup positions: one with the knees maximally flexed, and one with the knees less flexed. The start handles and touchpad were instrumented with multi-axial force sensors. Activity of major hip and knee extensors was measured using surface electromyography. Body position in the sagittal plane was recorded using high-speed cameras. There was no overall difference in time to 10 m between the two conditions (p = 0.36, dz = 0.12), but some participants showed differences as large as 0.12 s in time to 10 m between start conditions. We observed that starts performed from a setup position with less knee flexion had an average 0.07 m greater head entry distance (p = 0.07, dz = 0.53), while starts from a setup position with maximal knee flexion had an average 0.2 m/s greater takeoff velocity (p = 0.02, dz = 0.78). Both head entry distance and takeoff velocity are related to start performance, suggesting each position may optimize different aspects of the backstroke start. Coaches should assess athletes individually to determine which position is optimal.

Knee Strength Capabilities and Slip Severity

2009 ◽  
Vol 25 (2) ◽  
pp. 140-148 ◽  
Author(s):  
Sarah A. Wyszomierski ◽  
April J. Chambers ◽  
Rakié Cham
Keyword(s):  
Muscle Strength ◽  
Knee Flexion ◽  
Age Groups ◽  
Peak Torque ◽  
Knee Extension ◽  
Health Concern ◽  
Young Males ◽  
Motion Data ◽  
Flexion Extension ◽  
Muscle Moments

Slips and falls are a serious public health concern in older populations. Reduced muscle strength is associated with increased age and fall incidence. Understanding the relationships between specific joint muscle strength characteristics and propensity to slip is important to identify biomechanical factors responsible for slip-initiated falls and to improve slip/fall prevention programs. Knee corrective moments generated during slipping assist in balance recovery. Therefore, the study goal was to investigate the relationship between knee flexion/extension strength and slip severity. Isometric knee flexion/extension peak torque and rate of torque development (RTD) of the slipping leg were measured in 29 young and 28 older healthy subjects. Motion data were collected for an unexpected slip during self-paced walking. Peak slip velocity (PSV) of the slipping heel served as a slip severity measure. Within-sex and age group regressions relating gait speed-controlled PSV to strength of the slipping leg revealed significant inverse PSV-knee extension peak torque and PSV-knee flexion/extension RTD relationships in young males only. Differences in PSV-strength relationships between sex and age groups may be caused by greater ranges of strength capabilities in young males. In conclusion, the ability to generate higher, more rapid knee flexion/extension muscle moments (greater peak torque/RTD) may assist in recovery from severe slips.

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