Hip Extension Torque Research Articles

Reliability of a New Stabilized Dynamometer System for the Evaluation of Hip Strength

Background:Hip strength is associated with numerous orthopaedic and neuromuscular injuries and/or pathologies and may be assessed with a variety of anatomic testing positions and techniques. Isokinetic dynamometers are generally too cumbersome and intricate for efficient use in mass screenings (for prognostic studies of risk for injury) as well as with special populations. The reliability of isometric testing devices has demonstrated varied reliability, generally examining only 1 or 2 motions of the hip and reporting values of force, not torque. Consequently, there is a need for an efficient hip strength-testing device to quantify torque that tests subjects in 1 anatomic position, while evaluating multiple hip motions.Hypothesis:Evaluation of supine hip abduction, adduction, flexion, and extension torque using a new stabilized dynamometer system will produce good to excellent intra- and interexaminer reliability results.Study Design:A blinded, randomized, repeated-measures study design was used in this descriptive laboratory investigation.Methods:Supine isometric hip flexion, extension, abduction, and adduction torques were evaluated with a cage-stabilized dynamometer in 19 collegiate and professional-level ice hockey athletes by 2 investigators at 3 time intervals. Inter- and intrarater reliability was assessed.Results:Supine hip flexion, extension, abduction, and adduction torque was performed with good to excellent inter- and intrarater reliability (intraclass correlation coefficients ranging from 0.74 to 0.92 and 0.78 to 0.92, respectively) for all motions tested.Conclusions:We have developed an isometric hip strength-testing device that can be assembled around an examination table to efficiently and reliably evaluate torque developed for multiple motions of the hip.Clinical Relevance:This device and testing protocol may be used to efficiently evaluate hip strength in numerous settings; it allows decreased subject burden and increased comfort (which may be important following an injury in case-control investigations); and it may be well tolerated when testing athletes as well as special populations in the clinical setting.

片脚踏切を用いたリバウンド型ジャンプの動作および力発揮特性：両脚踏切を用いたリバウンド型ジャンプと比較して

The present study was conducted to clarify points for attention, and to determine an effective method for the single-leg rebound-type jump (SRJ) and double-leg rebound-type jump (DRJ) in plyometrics, by investigating the joint kinematics and kinetics of the takeoff leg in the sagittal plane. Twelve male track and field athletes (sprinters and jumpers) performed the SRJ and DRJ with maximal effort. Jumping motions in the sagittal plane were videotaped with a high-speed video camera (300 Hz), and ground reaction force was recorded with a force platform (1000 Hz). Kinematics and kinetics were calculated. To evaluate the force output characteristics for a single leg in the DRJ, the ground reaction force was divided into half, and the data were used to calculate the other kinetic parameters. The overall results of these analyses were as follows: 1. In the SRJ, the jump height for a single leg and the landing height for a single leg were higher than in the DRJ because of the higher mechanical power used during the eccentric and concentric phases. 2. In the SRJ, the negative relative work at the ankle joint was smaller and the negative and positive relative work at the hip joint was larger than in the DRJ. These results affected the characteristics of the SRJ in that although the jump height was higher for a single leg because of the greater mechanical work, the force output time was longer. 3. In the SRJ, the joint extension torque at the hip joint was larger than that in the DRJ. This may have been caused by the greater landing height for a single leg, higher body weight on a single leg, and the leg swing motion. 4. The RJ-index for the SRJ was correlated with that for the DRJ. Moreover, the RJ-index for the SRJ was affected by the joint torque and joint torque power at the ankle and hip joints. These results suggest that the DRJ and SRJ are effective training tools for improving both technique and force output ability in order to (1) prioritize the power output at the ankle plantar flexor in the DRJ and (2) prioritize the power output at the hip extensor and increase the ground reaction force and hip extension torque by leg swing motion for the SRJ. These findings are useful for clarifying the points for attention and for developing an effective method of using the SRJ and DRJ in plyometrics.

Prolonged electrical stimulation over hip flexors increases locomotor output in human SCI

Objectives The objective of this study was to determine whether enhanced feedback from thigh afferents improves locomotor output in human spinal cord injury (SCI). Methods The effects of afferent feedback originating from the upper thigh muscles on locomotion was examined using electrical stimulation in 10 subjects with incomplete SCI and three neurologically intact controls during robotic-assisted treadmill walking. Electrical stimulation consisted of 20 pulses at 30 Hz, applied bilaterally to the skin of the medial thigh, approximately over the sartorius muscle. The stimulation was applied at four different phases of the gait cycle. Torque responses of hip and knee joints and electromyograms of both legs were recorded during baseline with no stimulation, stimulation, and post-stimulation. Results During stimulation, enhanced hip and knee extension and flexion torque responses were observed during the stance and swing phases, respectively, for all four different stimulation conditions. Larger hip extension torque was observed when the stimulation was applied during the stance phase and the transition from stance to swing. Conclusions Enhanced afferent feedback produced by electrical stimulation may increase the excitability of the spinal cord locomotor circuits in human SCI. Significance Results from this study emphasize the contribution of sensory information from thigh muscles, particularly the sartorius muscle afferents, to locomotor control in human SCI during treadmill walking.

Preventing Ischial Pressure Ulcers: II. Biomechanics

Background:Pressure ulcers (PUs) are common and debilitating wounds that arise when immobilized patients cannot shift their weight. Neuromuscular Electrical Stimulation (NMES) has been investigated for Pressure Ulcer Prevention (PUP) for over 20 years. Historically gluteus maximus (GM) has been considered an important actuator in attempting to redistribute seated pressures through NMES.Methods:Analysis of skeletal biomechanics to quantify the value of GM relative to hamstring hip extensors (HS), using muscle moment models based on torques and rigid body mass estimates from the literature. Surface stimulation experiments (n= 10 + 1,non-paralyzed) to validate model and identify promising stimulation sites and treatment strategies that would approximate healthy biomechanics.Results:Literature values and Rigid Body Analysis estimate: ~63 Nm extensor torque requirement calculated for complete ipsilateral unloading of the buttocks. Muscle Moment Analysis: GM can provide 70% of total hip extensor torque when walking vs. 18% when seated. HS can provide 100 Nm hip extension torque when seated, exceeding 63 Nm requirement. Surface Stimulation: ipsilateral seated interface pressure mean −26% during HS stimulation vs. +16% with GM; peak pressure area −94% HS vs. +213% GM.Conclusions:GM activation reduces disuse atrophy and improves circulation, but appears neither required, nor desired, for unloading when seated. HS stimulation alone should be capable of sufficient unloading. This new proposed approach is explored clinically in companion paper III.

Preventing ischial pressure ulcers: II. Biomechanics

Background: Pressure ulcers PUs are common and debilitating wounds that arise when immobilized patients cannot shift their weight. Neuromuscular Electrical Stimulation NMES has been investigated for Pressure Ulcer Prevention PUP for over 20 years. Historically gluteus maximus GM has been considered an important actuator in attempting to redistribute seated pressures through NMES. Methods: Analysis of skeletal biomechanics to quantify the value of GM relative to hamstring hip extensors HS, using muscle moment models based on torques and rigid body mass estimates from the literature. Surface stimulation experiments n = 10 + 1, non-paralyzed to validate model and identify promising stimulation sites and treatment strategies that would approximate healthy biomechanics. Results: Literature values and Rigid Body Analysis estimate: ~63 Nm extensor torque requirement calculated for complete ipsilateral unloading of the buttocks. Muscle Moment Analysis: GM can provide 70% of total hip extensor torque when walking vs. 18% when seated. HS can provide 100 Nm hip extension torque when seated, exceeding 63 Nm requirement. Surface Stimulation: ipsilateral seated interface pressure mean -26% during HS stimulation vs. +16% with GM; peak pressure area -94% HS vs. +213% GM. Conclusions: GM activation reduces disuse atrophy and improves circulation, but appears neither required, nor desired, for unloading when seated. HS stimulation alone should be capable of sufficient unloading. This new proposed approach is explored clinically in companion paper III.

ACL Research Retreat V

ACL Research Retreat V

Hamstring muscle forces prior to and immediately following an acute sprinting-related muscle strain injury

A thorough understanding of the biomechanics of the hamstrings during sprinting is required to optimise injury rehabilitation and prevention strategies. The main aims of this study were to compare hamstrings load across different modes of locomotion as well as before and after an acute sprinting-related muscle strain injury. Bilateral kinematic and ground reaction force data were captured from a single subject whilst walking, jogging and sprinting prior to and immediately following a significant injury involving the right semitendinosis and biceps femoris long head muscles. Experimental data were input into a three-dimensional musculoskeletal model of the body and used, together with optimisation theory, to determine lower-limb muscle forces for each locomotor task. Hamstrings load was found to be greatest during terminal swing for sprinting. The hamstrings contributed the majority of the terminal swing hip extension and knee flexion torques, whilst gluteus maximus contributed most of the stance phase hip extension torque. Gastrocnemius contributed little to the terminal swing knee flexion torque. Peak hamstrings force was also substantially greater during terminal swing compared to stance for sprinting, but not for walking and jogging. Immediately following the muscle strain injury, the hamstrings demonstrated an intolerance to perform an eccentric-type contraction. Whilst peak hamstrings force during terminal swing did not decrease post-injury, both peak hamstrings length and negative work during terminal swing were considerably reduced. These results lend support to the paradigm that the hamstrings are most susceptible to muscle strain injury during the terminal swing phase of sprinting when they are contracting eccentrically.

Age and Gender Differences in Hip Extension and Flexion Torque Steadiness

Background: Lower extremity torque steadiness has been shown to be an independent predictor of functional performance in older women. Hip muscle function is crucial for many types of activities of daily living, yet existing studies investigating torque steadiness for lower extremities are limited to assessing steadiness at the knee and ankle. Objective: The purpose of this study was to compare age and gender differences in hip extension (HE) and flexion (HF) strength, torque steadiness, and torque accuracy (TA). Methods: Twenty young adults (10 men, 10 women; age 24.0 ± 2.2 years) and 21 older adults (11 men, 10 women; age 65.4 ± 4.5 years) matched across age for height and body mass participated. Dominant leg HE and HF isometric strength was assessed by maximal voluntary contractions (MVC); relative (5, 25 and 50% MVC) and absolute (25 Nm) torque steadiness were assessed as standard deviation and coefficient of variation of torque fluctuations, and TA was determined as the mean deviation from target torque levels. Results: MVC was lower for HF than HE (p = 0.007), but HE had greater torque fluctuations (p < 0.05). For HE, the coefficient of variation of 5% MVC was greater for older than young adults (p < 0.05) and greater for women than men (p < 0.05). For HF torque steadiness there were no age or gender differences (p > 0.05). For both HE and HF, older adults were less accurate (higher TA) than their young counterparts at 25 Nm (p < 0.022). Conclusions: Our results indicate older as compared to young adults, and women as compared to men are less steady (greater torque fluctuations) in HE at 5% MVC target torque levels, but not at higher torque levels. For HF, torque steadiness is similar across low to high target torque levels in both genders and across younger and older adults. For both HE and HF, TA is impaired in older compared to young adults at absolute target torque levels, but not at relative torque levels.

Effect of arm swing direction on forward and backward jump performance

This study quantified and compared how the directional differences in arm swing affected mechanical and physiological parameters during forward and backward jumping. Seven subjects maximally performed three types of forward and backward squat jumps—no arm swing (FJ, BJ), forward arm swing (FJF, BJF), and backward arm swing (FJB, BJB) from a force platform. All performances were captured with a 3-D motion capture system. Electromyograms (EMGs) of the lower extremity muscles were obtained. Variables were calculated by combining kinematic and kinetic data. The jump displacement and center of mass velocity at take-off were significantly larger in FJF than in FJ or FJB and larger in BJB than in BJ or BJF, suggesting that the best performance was obtained by employing the same arm swing direction as a given jump direction. The total work by three lower and two upper extremity joints was significantly larger in FJF than in FJ or FJB and larger in BJB than in BJ or BJF. For the lower extremity joints, hip work was the greatest in FJF and BJB. The integrated EMG of the biceps femoris when the hip power was produced was significantly larger in FJF and BJB than under other conditions. These results suggest that if the arm swing direction is the same as a given jump direction, the activation level of the hip extensor is greater to counter large loads which make the hip joint flex during the push-off phase, which result in increased hip extension torque, power, and work.

Lower Extremity Muscle Strength in 6- to 8-Year-Old Children Using Hand-Held Dynamometry

The purposes of the study were to establish isometric torque reference values for healthy 6- to 8-year-old children for 6 lower extremity muscles and determine the effects of gender, age, height, weight, and physical activity upon strength. A hand-held dynamometer was used to obtain force/torque values for 154 children. Age-referenced force/torque and cutoff values are provided for each muscle group. Torque increased with age and height for all muscles and with weight for all muscles except knee extensors. No gender differences were found. Children who participated in 3 or more hours per week in organized sports were stronger in 4 of 6 muscles; the number of hours spent in active play did not affect torque. This study provides hand-held dynamometer strength reference values to enable clinicians to determine if clients of the same age, height, and weight have muscle weakness.

The robustness of age-related gait adaptations: Can running counterbalance the consequences of ageing?

Previous studies showed age-related redistribution of joint torques from ankle joint plantar flexion to hip joint extension in gait. In the present study it was hypothesized that running can prevent the occurrence of this joint torque redistribution. Four groups of subjects participated in this study (young and elderly both physically active and inactive). All subjects walked at a comfortable, preferred velocity and at an imposed velocity of 1.5 m/s. Kinematics of lower limb segments and ground reaction forces were assessed. Inverse dynamics method was applied to determine torques around ankle, knee and hip joints. A redistribution of joint torques from plantar flexion to hip joint extension was found to occur in both active and inactive elderly. However, the active elderly had a larger increase of the hip extension torque. By this they are able to maintain the support torque at the level of young subjects. Inactive elderly displayed reduced support torques. It is concluded that the age-related redistribution of joint torques is an important phenomenon. Frequent running does not prevent this shift. Active elderly increase this redistribution to compensate for muscle function reduction.

The supine hip extensor manual muscle test: A reliability and validity study

Perry J, Weiss WB, Burnfield JM, Gronley JK. The supine hip extensor manual muscle test: a reliability and validity study. Arch Phys Med Rehabil 2004;85:1345–50. Objectives To define the relative hip extensor muscle strengths values identified by the 4 grades obtained with a supine manual muscle test (MMT) and to compare these values with those indicated by the traditional prone test. Design Comparison of 4 manual supine strength grades with isometric hip extension joint torque; κ statistic-determined interrater reliability, and analyses of variance identified between grade differences in torque. Setting Pathokinesiology laboratory. Participants Adult volunteers recruited from local community and outpatient clinics. Reliability testing: 16 adults with postpolio (31 limbs). Validity testing (2 groups): 18 subjects without pathology (18 limbs), and 26 people with clinical signs of hip extensor weakness (51 limbs). Interventions Not applicable. Main Outcome Measures Supine hip extensor manual muscle grade and isometric hip extension torque. Results Reliability testing showed excellent agreement (82%). Subjects with pathology had significant differences in mean torque ( P<.01) for the assigned grade 5 (176Nm), grade 4 (103Nm), grade 3 (67Nm), and grade 2 (19Nm). Healthy adults showed significant differences between grade 5 (212Nm) and grade 4 (120Nm) in mean torque ( P<.05). Conclusions The supine MMT is a reliable and valid method with which to assess hip extension strength.

Kinetic Analysis of Backward Giant Swing on Parallel Bars

The purpose of this study was to investigate the kinetic characteristics of backward giant swing on parallel bars (PB) compared with those of backward giant swing on horizontal bar (HB). The subjects were six male skillful university gymnasts. Their performances of PB and HB were videotaped with a digital video camera to calculate the knee, shoulder, and hip joint angle, joint torque, joint power, and mechanical work from two-dimensional coordination of the body landmarks. The mechanical negative work done by hip extension torque leading to hang phase of PB were larger than those of HB. During upward phase from hang, the shoulder extension torque of PB was exerted longer period of time than HB, with the result that mechanical positive work done by shoulder extension torque of PB was larger than that of HB. For effective training of backward giant swing on parallel bars, the coach has to recognize their characteristic differences from those of horizontal bar.

Effect of the movement speed of resistance training exercises on sprint and strength performance in concurrently training elite junior sprinters

The aim of this study was to determine the effects of 7 weeks of high- and low-velocity resistance training on strength and sprint running performance in nine male elite junior sprint runners (age 19.0 - 1.4 years, best 100 m times 10.89 - 0.21 s; mean - s ). The athletes continued their sprint training throughout the study, but their resistance training programme was replaced by one in which the movement velocities of hip extension and flexion, knee extension and flexion and squat exercises varied according to the loads lifted (i.e. 30-50% and 70-90% of 1-RM in the high- and low-velocity training groups, respectively). There were no between-group differences in hip flexion or extension torque produced at 1.05, 4.74 or 8.42 rad·s -1 , 20 m acceleration or 20 m 'flying' running times, or 1-RM squat lift strength either before or after training. This was despite significant improvements in 20 m acceleration time ( P ≪ 0.01), squat strength ( P ≪ 0.05), isokinetic hip flexion torque at 4.74 rad·s -1 and hip extension torque at 1.05 and 4.74 rad·s -1 for the athletes as a whole over the training period. Although velocity-specific strength adaptations have been shown to occur rapidly in untrained and non-concurrently training individuals, the present results suggest a lack of velocity-specific performance changes in elite concurrently training sprint runners performing a combination of traditional and semi-specific resistance training exercises.

The influence of lower extremity joint torque on gait characteristics in elderly men

Burnfield JM, Josephson KR, Powers CM, Rubenstein LZ. The influence of lower extremity joint torque on gait characteristics in elderly men. Arch Phys Med Rehabil 2000;81:1153-7. Objective: To examine the relation between certain lower extremity isokinetic muscle torque capabilities and selected stride characteristics for a group of elderly, sedentary men. Study Design: Descriptive analysis of convenience sample. Setting: Veterans Administration (VA) ambulatory care center. Subjects: Eighty-one elderly men, capable of independent ambulation, were recruited from outpatient clinics and the local community (mean age, 74.7yr). Main Outcome Measures: Maximal isokinetic torque in the sagittal plane of hip, knee, and ankle muscles; stride characteristics of speed, stride length, and cadence recorded during walking at a self-selected velocity. Results: Stepwise regression analysis revealed that hip extension torque was the only significant independent predictor for free walking speed, stride length, and cadence, and accounted for 37% (r =.611), 35% (r =.590), and 12% (r =.341) of the total variance, respectively. Other joint torques correlated with gait parameters but did not add significantly to the multivariate model. Conclusions: Hip extension torque was the only significant independent predictor for free walking velocity, stride length, and cadence in this group. These results support the idea that strengthening the hip extensors may improve stride characteristics in elderly individuals. © 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

An Investigation of the Relationship between Hip Extension Torque, Hip Extension Velocity, and Muscle Activation

The purpose of this study was to determine if the characteristic Hill model, used to describe me force–velocity relationship for isolated tetanically stimulated muscle, could be modified and used to describe me torque–velocity behavior of me hip for maximally and submaximally stimulated hip extensor muscles. Fourteen subjects performed hip extension movements at effort levels of 100%, 70%, and 40% of a maximum isometric effort. A solenoid provided isometric resistance to hip extension. Once the desired effort level was achieved, as indicated by me isometric force, the solenoid released and me hip moved against an opposing elastic resistance equal to 75%, 50%, 25%, and 0% of the specified effort level. An electrogoniometer quantified hip angle. Hip velocity was determined by numerically differentiating the angle data. Torque-velocity-activation (or effort level) data were determined for each trial. Model parameters were determined to give me best fit to the data for each subject. Average parameter values were determined for each gender and for the entire group. The modified Hill-type model, Tm = (Tmax · A − K1 · ω)/(K2 · ω + 1), accurately describes me relationship between joint torque (Tm), maximum isometric joint torque (Tmax), joint velocity (ω), and muscle activation level (A) for subject-specific parameters (K1 and K2), but not for parameters averaged across genders or the entire group. Values for Tmax, K1, and K2 ranged from 90 to 385 Nm, 6.1 to 47.9 Nms, and 0.030 to 0.716 s, respectively.

Changes in Hip Muscles After Above-Knee Amputation

To learn about the changes appearing in hip muscles after an above-knee amputation, 3-dimensional reconstructions of the hip and thigh region of 12 patients with above-knee amputations were made based on transverse magnetic resonance images. In all patients, the amputations were done at least 2 years before the study and were necessitated by trauma or osteosarcoma. The results show that, at higher amputation levels, the geometry of the once-biarticular muscles was changed. The cleaved muscles (40%-60%) and the intact muscles (0-30%) at the amputated side were atrophied. The amount of atrophy of the intact muscles at the amputated side was related to stump length. To avoid an abduction contracture in 8 patients with amputations, the iliotibial tract was not fixed. In 4 of these 8 patients, a flexion contracture was visible. If the tract was not fixed, the hip extension torque of the gluteus maximus, which inserts into the tract, decreased. As a result, the risk of appearance of a flexion contracture increased because the strongest hip flexor (iliopsoas muscle) was not involved in the amputation. Abduction contracture could be avoided only if the hip adductors were fixed accurately, especially at higher amputation levels.

An analysis of sit-to-stand movements.

We analyzed the movements involved in rising from a knee-high chair in 12 healthy men weighing within +/- 10% of standard body weight. A regular series of transition points was observed in the angles of the hip, knee, and ankle joints throughout the sit-to-stand movement, which was classified into six stages. As the duration of sit-to-stand movements increased, the duration of Stage 2 decreased, whereas Stage 3 grew longer. The durations of stages 4 and 5 remained constant. We also calculated the minimum unilateral hip and knee extension torque per weight in kilograms required for natural sit-to-stand movements, or N-Stand (1.7-2.3 seconds), and found that minimum hip extension torque was 0.7Nm and minimum knee extension torque was 0.9Nm. The minimum hip and knee extension torque required for N-Stand corresponds to a mean 27% and 30%, respectively, of the actual maximum hip and knee extension torque.

The Relative Strength of the Hamstrings during Hip Extension

The role of the hamstrings in extension of the hip was determined in eight normal subjects by measuring maximum isometric hip extension torque in different positions of hip flexion before and after sciatic-nerve block. Total hip extensor strength increased more than twofold as the hip was flexed from zero to 90 degrees. Following sciatic-nerve block, hip extension strength was reduced approximately 50 per cent in all positions of hip flexion. The hamstrings accounted for approximately one-third of total measured extensor torque.