Impact Peak, Knee Muscle Cocontraction, and Knee Angle during Early Contact of Running in Children with Diplegic Cerebral Palsy

2021 ◽  
Author(s):  
Sirinart Laibsirinon
Keyword(s):  
Cerebral Palsy ◽  
Knee Angle ◽  
Impact Peak ◽  
Peak Knee ◽  
Knee Muscle

scholarly journals Effects of 12-week cadence retraining on impact peak, load rates and lower extremity biomechanics in running

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9813
Author(s):  
Junqing Wang ◽  
Zhen Luo ◽  
Boyi Dai ◽  
Weijie Fu
Keyword(s):  
Lower Extremity ◽  
Impact Force ◽  
Peak Load ◽  
Control Group ◽  
Initial Contact ◽  
Vertical Load ◽  
Impact Peak ◽  
Peak Knee ◽  
Running Injuries ◽  
Lower Extremity Biomechanics

Background Excessive impact peak forces and vertical load rates are associated with running injuries and have been targeted in gait retraining studies. This study aimed to determine the effects of 12-week cadence retraining on impact peak, vertical load rates and lower extremity biomechanics during running. Methods Twenty-four healthy male recreational runners were randomised into either a 12-week cadence retraining group (n = 12), which included those who ran with a 7.5% increase in preferred cadence, or a control group (n = 12), which included those who ran without any changes in cadence. Kinematics and ground reaction forces were recorded simultaneously to quantify impact force variables and lower extremity kinematics and kinetics. Results Significantly decreased impact peak (1.86 ± 0.30 BW vs. 1.67 ± 0.27 BW, P = 0.003), vertical average load rates (91.59 ± 18.91 BW/s vs. 77.31 ± 15.12 BW/s, P = 0.001) and vertical instantaneous load rates (108.8 ± 24.5 BW/s vs. 92.8 ± 18.5 BW/s, P = 0.001) were observed in the cadence retraining group, while no significant differences were observed in the control group. Foot angles (18.27° ± 5.59° vs. 13.74° ± 2.82°, P = 0.003) and vertical velocities of the centre of gravity (CoG) (0.706 ± 0.115 m/s vs. 0.652 ± 0.091 m/s, P = 0.002) significantly decreased in the cadence retraining group at initial contact, but not in the control group. In addition, vertical excursions of the CoG (0.077 ± 0.01 m vs. 0.069 ± 0.008 m, P = 0.002) and peak knee flexion angles (38.6° ± 5.0° vs. 36.5° ± 5.5°, P < 0.001) significantly decreased whilst lower extremity stiffness significantly increased (34.34 ± 7.08 kN/m vs. 38.61 ± 6.51 kN/m, P = 0.048) in the cadence retraining group. However, no significant differences were observed for those variables in the control group. Conclusion Twelve-week cadence retraining significantly increased the cadence of the cadence retraining group by 5.7%. This increased cadence effectively reduced impact peak and vertical average/instantaneous load rates. Given the close relationship between impact force variables and running injuries, increasing the cadence as a retraining method may potentially reduce the risk of impact-related running injuries.

Age- and sex-associated differences in isokinetic knee muscle endurance between young children and adults

2009 ◽  
Vol 34 (4) ◽  
pp. 725-731 ◽  
Author(s):  
Mark B.A. De Ste Croix ◽  
Martine A. Deighan ◽  
Sebastien Ratel ◽  
Neil Armstrong
Keyword(s):  
Young Children ◽  
Peak Torque ◽  
Knee Extension ◽  
Total Work ◽  
Adult Males ◽  
Significant Interaction Effect ◽  
Peak Knee ◽  
Knee Muscle ◽  
Main Effects ◽  
Age And Sex

The purpose of this study was to examine the age- and sex-associated differences of repeated isokinetic knee extension and flexion. Fifty one participants, 30 young children (16 boys and 14 girls; aged 11 and 12 years) and 21 adults (9 males and 12 females; aged 18–35 years), agreed to participate in the study. Isokinetic concentric peak knee extension (PET) and flexion (PFT) torque were measured using a calibrated Biodex System 3. Participants performed 4 concentric extension–flexion cycles with maximum effort; after a 2 min rest, 50 continuous concentric cycles were performed at 1.56 rad·s–1. Total work of the extensors (WKEX) and flexors (WKFL) for the complete 50 repetitions was recorded. Average peak torque and average work for the first and last 3 repetitions were calculated to represent the percentage decline in torque and work. There were no significant differences between groups in the peak torque generated during the pretrial and endurance task, suggesting that participants gave a maximal effort at the start of the endurance task. There was a significant interaction effect in the total work done for both extensors and flexors, with adult males producing the greatest amount of work (6622 and 3444 J, respectively). When total work was divided by body mass, there were no significant sex effects, only main effects for group. The percentage decline for PET (40% vs. 60%), PFT (50% vs. 65%), WKET (43% vs. 61%), and WKFL (60% vs. 69%) demonstrated significant main effects for group, with greater fatigue in adults. We found no significant sex effect for fatigue. This study concludes that females do not resist fatigue from repeated isokinetic muscle actions to a greater extent than males, and that the greater fatigue in adults than in children is probably a product of greater initial torque production and work performed.

Sagittal Plane Peak Knee Angle Variability During Distance Running Training And Race Speeds

2017 ◽  
Vol 49 (5S) ◽  
pp. 133
Author(s):  
Christopher T. Robertson ◽  
Jaclyn O’Loughlin ◽  
Jeffrey T. Wight
Keyword(s):  
Sagittal Plane ◽  
Distance Running ◽  
Knee Angle ◽  
Running Training ◽  
Peak Knee

scholarly journals Validity and Reliability of a Virtual Reality Game in Evaluating the Projected Frontal Plane Knee Angle When Landing From a Drop Vertical Jump

2018 ◽  
Vol 27 (4) ◽  
Author(s):  
Kathryn Mills ◽  
Aula Idris ◽  
Thu-An Pham ◽  
John Porte ◽  
Mark Wiggins ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Knee Angle ◽  
Validity And Reliability ◽  
Limits Of Agreement ◽  
Specificity And Sensitivity ◽  
Peak Knee ◽  
Knee Abduction ◽  
Vertical Jumps

Objectives: To determine the validity and reliability of the peak frontal plane knee angle evaluated by a virtual reality (VR) netball game when landing from a drop vertical jump. Study Design: Laboratory. Methods: Forty participants performed 3 drop vertical jumps evaluated by 3-dimensional motion analysis and 3 drop vertical jumps evaluated by the VR game. Limits of agreement for the peak projected frontal plane knee angle and peak knee abduction were determined. Participants were given a consensus category of “above threshold” or “below threshold” based on a prespecified threshold angle of 9° during landing. Classification agreement was determined using kappa coefficient, and accuracy was determined using specificity and sensitivity. Ten participants returned 1 week later to determine intrarater reliability, standard error of the measure, and typical error. Results: The mean difference in detected frontal plane knee angle was 3.39° (95% confidence interval [CI], 1.03° to 5.74°). Limits of agreement were −10.27° (95% CI, −14.36° to −6.19°) to 17.05° (95% CI, 12.97° to 21.14°). Substantial agreement, specificity, and sensitivity were observed for the threshold classification (κ = .66; 95% CI, .42 to .88; specificity = 0.96; 95% CI, 0.78 to 1.0; and sensitivity = 0.75; 95% CI, 0.43 to 0.95). The game exhibited acceptable reliability over time (intraclass correlation coefficient, ICC3,1 = .844), and error was approximately 2°. Conclusion: The VR game reliably evaluated a projected frontal plane knee angle. Although the knee angle detected by the VR game is strongly related to peak knee abduction, the accuracy of detecting the exact angle was limited. A threshold approach may be a more accurate approach for gaming technology to evaluate frontal plane knee angles when landing from a jump.

scholarly journals Relationship between Knee Muscle Strength and Fat/Muscle Mass in Elderly Women with Knee Osteoarthritis Based on Dual-Energy X-Ray Absorptiometry

2020 ◽  
Vol 17 (2) ◽  
pp. 573
Author(s):  
Xini Zhang ◽  
Xiaoyu Pan ◽  
Liqin Deng ◽  
Weijie Fu
Keyword(s):  
Muscle Strength ◽  
Knee Osteoarthritis ◽  
Muscle Mass ◽  
Elderly Women ◽  
Knee Extension ◽  
Mass Percentage ◽  
Peak Knee ◽  
Total Body ◽  
Knee Muscle ◽  
Knee Muscle Strength

Purpose: This study aimed to examine the characteristics and correlation of knee muscle strength and body composition (fat and muscle mass) among elderly women aged 60–70 years with knee osteoarthritis. The present study hypothesized that the muscle mass and the peak torques of the knee joints were considerably low in the knee osteoarthritis (KOA) group. Methods: A total of 47 elderly women aged 60–70 years were recruited from Yangpu District in Shanghai and assigned to the knee osteoarthritis (n = 25, KOA) or healthy control group (n = 22, CON). The knee extension/flexion isokinetic strength measurements were conducted on an isokinetic dynamometer at angular velocities of 90°/s. Dual-energy X-ray absorptiometry was used to measure the body composition (fat and muscle mass in the whole body and lower limbs). The independent sample t-test was employed to determine the effects of knee osteoarthritis on each variable, and the Pearson correlation analysis was used to investigate the correlation between the body composition and knee muscle strength. Results: Compared with the CON, the KOA exhibited the following: (1) Lower absolute peak knee extension torque (66.02 ± 10.57 vs. 56.61 ± 14.69 Nm), relative peak knee extension (1.11 ± 0.19 vs. 0.89 ± 0.26 Nm/kg), and flexion torque (0.62 ± 0.15 vs. 0.54 ± 0.16 Nm/kg, p < 0.05); (2) greater relative peak torque ratio of the knee extension and flexion (0.55 ± 0.08 vs. 0.62 ± 0.15, p < 0.05); and (3) lower total body muscle mass percentage (63.24% ± 4.50% vs. 59.36% ± 3.94%), particularly in the lower limbs (19.96% ± 1.51% vs. 18.47% ± 1.49%, p < 0.05). Furthermore, the total body fat mass percentage was negatively associated with the relative peak knee extension and flexion torque regardless of the group (p < 0.05). The total body muscle mass percentage was positively associated with the relative peak knee extension torque in the two groups and the relative peak knee flexion torque in the CON (p < 0.05). Conclusion: For elderly women with knee osteoarthritis, knee muscle strength decreases significantly, especially for the extensor strength. Moreover, compared with fat mass, the index of muscle mass is more sensitive in detecting the decrease in knee joint torque. Therefore, rather than weight loss alone, the quadriceps muscle and the rear-thigh muscles, which maintain the stability of knee joints during rehabilitation training, should be strengthened emphatically to improve muscle mass.

The Gliding and Push-Off Technique of Male and Female Olympic Speed Skaters

1989 ◽  
Vol 5 (2) ◽  
pp. 119-134 ◽  
Author(s):  
Ruud W. de Boer ◽  
Kim L. Nilsen
Keyword(s):  
Elite Athletes ◽  
Plantar Flexion ◽  
Weather Conditions ◽  
Complex Nature ◽  
Knee Angle ◽  
Large Numbers ◽  
Peak Knee ◽  
Angular Velocities ◽  
Winter Olympic Games ◽  
Trunk Position

The 1988 Winter Olympic Games provided a unique opportunity to study large numbers of optimally prepared speed skaters during ideal ice and weather conditions for all the competitors (indoor Olympic Oval in Calgary). In this study a kinematic analysis was conducted of the gliding and push-off technique during the Men’s and Ladies' 1,500-m and 5,000-m races. Statistical analysis showed that factors such as trunk position, preextension knee angle, and peak knee and hip angular velocities failed to correlate with mean lap speed. Within such a homogeneous group of elite athletes it was found that the higher work per stroke of the faster skaters was correlated to a longer gliding phase and a more horizontally directed push-off. All skaters showed plantar flexion at the end of the stroke, which is undesirable and indicates the complex nature of the gliding and push-off technique in speed skating.

scholarly journals The Effect of Quadriceps Femoris Muscle Strengthening Exercises on Spasticity in Children With Cerebral Palsy

2001 ◽  
Vol 81 (6) ◽  
pp. 1215-1223 ◽  
Author(s):  
Eileen G Fowler ◽  
Teresa W Ho ◽  
Azuka I Nwigwe ◽  
Fredrick J Dorey
Keyword(s):  
Cerebral Palsy ◽  
Stretch Reflex ◽  
Quadriceps Femoris ◽  
Quadriceps Femoris Muscle ◽  
Muscle Strengthening ◽  
Pendulum Test ◽  
Single Bout ◽  
Before And After ◽  
Knee Muscle ◽  
Femoris Muscle

Abstract Background and Purpose. The Bobath neurodevelopmental treatment approach advised against the use of resistive exercise, as proponents felt that increased effort would increase spasticity. The purpose of this study was to test the premise that the performance of exercises with maximum efforts will increase spasticity in people with cerebral palsy (CP). Spasticity, in the present study, was defined as a velocity-dependent hyperexcitability of the muscle stretch reflex. Subjects. Twenty-four subjects with the spastic diplegic form of CP (mean age=11.4 years, SD=3.0, range=7–17) and 12 subjects without known neurological impairments (mean age=11.6 years, SD=3.5, range= 7–17) were assessed. Methods. Knee muscle spasticity was assessed bilaterally using the pendulum test to elicit a stretch reflex immediately before and after 3 different forms of right quadriceps femoris muscle exercise (isometric, isotonic, and isokinetic) during a single bout of exercise training. Pendulum test outcome measures were: (1) first swing excursion, (2) number of lower leg oscillations, and (3) duration of the oscillations. Results. There were no changes in spasticity following exercise between the 2 groups of subjects. Discussion and Conclusion. These results do not support the premise that exercises with maximum efforts increase spasticity in people with CP.

Knee moment-knee angle characteristics and muscle morphology in children with spastic cerebral palsy selected for medial hamstring lengthening

2015 ◽  
Vol 42 ◽  
pp. S48
Author(s):  
H. Haberfehlner ◽  
H. Maas ◽  
J. Harlaar ◽  
R. Brunner ◽  
J.G. Becher ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Spastic Cerebral Palsy ◽  
Knee Angle ◽  
Muscle Morphology
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