Work capacity during 30 days of bed rest with isotonic and isokinetic exercise training

1989 ◽  
Vol 67 (5) ◽  
pp. 1820-1826 ◽  
Author(s):  
J. E. Greenleaf ◽  
E. M. Bernauer ◽  
A. C. Ertl ◽  
T. S. Trowbridge ◽  
C. E. Wade
Keyword(s):  
Exercise Training ◽  
Knee Flexion ◽  
Bed Rest ◽  
Peak Torque ◽  
Total Work ◽  
Variable Intensity ◽  
Isokinetic Exercise ◽  
Peak Vo2 ◽  
Flexion Extension ◽  
Leg Exercise

The purpose was to test the hypothesis that twice daily, short-term, variable intensity isotonic and intermittent high-intensity isokinetic leg exercise would maintain peak O2 uptake (VO2) and muscular strength and endurance, respectively, at or near ambulatory control levels during 30 days of -6 degrees head-down bed rest (BR) deconditioning. Nineteen men (aged 32-42 yr) were divided into no exercise control (peak VO2 once/wk, n = 5), isokinetic (Lido ergometer, n = 7), and isotonic (Quinton ergometer, n = 7) groups. Exercise training was conducted in the supine position for two 30-min periods/day for 5 days/wk. Isotonic training was at 60-90% of peak VO2, and isokinetic training (knee flexion-extension) was at 100 degrees/s. Mean (+/- SE) changes (P less than 0.05) in peak VO2 (ml.m-1.kg-1) from ambulatory control to BR day 28 were 44 +/- 4 to 36 +/- 3, -18.2% (3.27-2.60 l/m) for no exercise, 39 +/- 4 to 40 +/- 3, +2.6% (3.13-3.14 l/min) for isotonic, and 44 +/- 3 to 40 +/- 2, -9.1% (3.24-2.90 l/min) for isokinetic. There were no significant changes in any groups in leg peak torque (right knee flexion or extension), leg mean total work, arm total peak torque, or arm mean total work. Mean energy costs for the isotonic and isokinetic exercise training were 446 kcal/h (18.8 +/- 1.6 ml.min-1.kg-1) and 214 kcal/h (8.9 +/- 0.5 ml.m-1.kg-1), respectively. Thus near-peak, variable intensity, isotonic leg exercise maintains peak VO2 during 30 days of BR, while this peak, intermittent, isokinetic leg exercise protocol does not.

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Spinal Cord Injury ◽  
Cardiac Output ◽  
Electrical Stimulation ◽  
Knee Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Leg Exercise ◽  
Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

scholarly journals KNEE ISOKINETIC TORQUE IMBALANCE IN FEMALE FUTSAL PLAYERS

2017 ◽  
Vol 23 (5) ◽  
pp. 352-356
Author(s):  
Ana Carolina de Mello Alves Rodrigues ◽  
Nathália Arnosti Vieira ◽  
Ana Lorena Marche ◽  
Juliana Exel Santana ◽  
Marco Aurélio Vaz ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Repeated Measures ◽  
Knee Flexion ◽  
Peak Torque ◽  
Joint Angles ◽  
Muscle Imbalance ◽  
Flexion Extension ◽  
Isokinetic Torque ◽  
Extensor Torque ◽  
Joint Range

ABSTRACT Introduction: The specificity of sports training can lead to muscle specialization with a possible change in the natural hamstring/quadriceps torque ratio (HQ ratio), constituting a risk factor for muscle injury at the joint angles in which muscle imbalance may impair dynamic stability. Objective: The aim was to evaluate the torque distribution of the hamstrings and quadriceps and the HQ ratio throughout the range of motion in order to identify possible muscle imbalances at the knee of female futsal athletes. Methods: Nineteen amateur female futsal athletes had their dominant limb HQ ratio evaluated in a series of five maximum repetitions of flexion/extension of the knee at 180°/second in the total joint range of motion (30° to 80°). The peak flexor and extensor torque and the HQ ratio (%) were compared each 5° of knee motion using one-way repeated measures ANOVA and Tukey’s post hoc test (p<0.05) to determine the joint angles that present muscular imbalance. Results: Quadriceps torque was higher than 50° to 60° of knee flexion, while hamstrings torque was higher than 55° to 65°. The HQ ratio presented lower values than 30° to 45° of knee flexion and four athletes presented values lower than 60%, which may represent a risk of injury. However, the HQ ratio calculated by the peak torque showed only one athlete with less than 60%. Conclusion: The HQ ratio analyzed throughout the knee range of motion allowed identifying muscle imbalance at specific joint angles in female futsal players.

Effect of leg exercise training on vascular volumes during 30 days of 6 degrees head-down bed rest

1992 ◽  
Vol 72 (5) ◽  
pp. 1887-1894 ◽  
Author(s):  
J. E. Greenleaf ◽  
J. Vernikos ◽  
C. E. Wade ◽  
P. R. Barnes
Keyword(s):  
Exercise Training ◽  
Bed Rest ◽  
Leg Exercise

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 Muscle Recruitment Pattern of The Hamstring Muscles in Hip Extension and Knee Flexion Exercises

2020 ◽  
Vol 72 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Osamu Yanagisawa ◽  
Atsuki Fukutani
Keyword(s):  
Knee Flexion ◽  
Biceps Femoris ◽  
Peak Torque ◽  
Total Work ◽  
Recruitment Pattern ◽  
Concentric Contractions ◽  
Hamstring Muscles ◽  
Long Head ◽  
S Peak ◽  
Hip Extension

AbstractWe aimed to compare dynamic exercise performance between hip extension exercises with different knee angles and between knee flexion exercises with different hip angles, and to investigate the recruitment pattern of the hamstrings in each exercise. Seven men performed 4 isokinetic exercises (3 maximal concentric contractions at 30°/s (peak torque) and 30 maximal concentric contractions at 180°/s (total work)): hip extension with the knee fully extended (HEke) and with the knee flexed at 90° (HEkf) and knee flexion with the hip fully extended (KFhe) and with the hip flexed at 90° (KFhf). The recruitment pattern of the hamstrings was evaluated in each exercise using magnetic resonance imaging (T2 calculation). The HEke condition showed significantly greater peak torque than the HEkf condition (p < 0.05). The KFhf condition had significantly greater peak torque and total work values than the KFhe condition (p < 0.05). Although the biceps femoris long head, semitendinosus, and semimembranosus had significantly increased post-exercise T2 values in the HEke (p < 0.05), KFhe, and KFhf conditions (p < 0.01), the T2 increase values were significantly greater under the KFhf than the HEke condition (p < 0.05). The semitendinosus showed a significantly greater T2 increase value than other muscles under both KFhe and KFhf conditions (p < 0.05). Performance of hip extension and knee flexion exercises increases when the hamstring muscles are in a lengthened condition. The hamstring muscles (particularly the semitendinosus) are more involved in knee flexion than in hip extension.

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.

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.

SUPINE VS SEATED ISOKINETIC KNEE FLEXION/EXTENSION JOINT ANGLE AT PEAK TORQUE

2001 ◽  
Vol 33 (5) ◽  
pp. S28
Author(s):  
D L. Provenzano ◽  
B W. Findley ◽  
L E. Brown ◽  
D E. Asper ◽  
C K. Drake ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Joint Angle ◽  
Peak Torque ◽  
Flexion Extension

Sex Differences in Lower Limb Proprioception and Mechanical Function Among Healthy Adults

Motor Control ◽  
2020 ◽  
Vol 24 (4) ◽  
pp. 571-587
Author(s):  
Xiaoyue Hu ◽  
Jingxian Li ◽  
Lin Wang
Keyword(s):  
Menstrual Cycle ◽  
Muscle Strength ◽  
Lower Limb ◽  
Knee Flexion ◽  
Plantar Flexion ◽  
Peak Torque ◽  
Isokinetic Muscle Strength ◽  
Flexion Extension ◽  
Hop Test ◽  
Limb Proprioception

Twenty-four healthy adults, including 12 females and 12 males, participated in the study. Each female participant completed three trials in three different phases of one menstrual cycle, which included follicular, ovulatory, and luteal phases. The study aimed to investigate whether there is any difference in joint kinetic sense, neuromuscular coordination, and isokinetic muscle strength (a) between healthy males and females at different phases of the menstrual cycle and (b) between females at different phases of the menstrual cycle. The outcome measures included the number of jumps in the square-hop test and ankle and knee proprioception, which were assessed by an electric-driven movable frame rotated at 0.4 deg/s and isokinetic muscle strength measured by a computerized dynamometer (Biodex). For the square-hop test (p = .006), ankle dorsiflexion/plantar flexion (p < .05), knee flexion/extension (p < .05), the relative peak torque of the isokinetic muscle strength at the 60° and 180° knee flexion/extension (p < .001), and the 30° and 120° ankle plantar flexion/dorsiflexion (p < .05) between females and males showed significant differences. For the females at different phases of the menstrual cycle, significant differences were found on ankle dorsiflexion (p = .003), plantar flexion (p = .023), knee extension (p = .029), the square-hop test (p = .036), and relative peak torque of isokinetic muscle strength at 180° knee flexion (p = .029). This study demonstrated that there are sex differences in lower limb proprioception and mechanical function. Females at ovulatory and luteal phases have better lower limb proprioception than at the follicular phase.

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