How Different Knee Flexion Angles Influence the Hip Extensor in the Prone Position

[Purpose] The present study examined the effects of knee flexion angle on hip extensor muscle activity. [Subjects and Methods] Twenty healthy subjects maintained knee flexion angles of 0°, 30°, 60°, 90° and 110° in the prone position and performed maximal voluntary contraction in hip extension. Maximum torque in hip extension at the different angles was measured, and surface electromyogram activities of the gluteus maximus (GM), biceps femoris (BF) and semitendinosus (ST) were recorded and normalized by the maximum voluntary isometric contraction (MVIC). [Results] The maximum torque of the hip extensor showed significant decreases between 0°and 60°, 90° and 110° of knee flexion. The muscle activity of BF was significantly high at 0°, and GM showed a significantly higher activity than both BF and ST at 60°, 90°and 110° of knee flexion. [Conclusion] The maximum torque in hip extension and muscle activities of BF and ST were significantly high at 0° but they decreased at knee flexion angles of more than 60°. Therefore, we consider that more than 60° of knee joint flexion is required to increase GM activity, and to reduce the muscle activities of BF and ST.Key words: Gluteus maximus, Hamstring muscle, Prone hip extension     

Comparison of lumbar repositioning error according to different lumbar angles in a flexion pattern (FP) subgroup of patients with non-specific chronic low back pain

[Purpose] This study determined the change in lumbar position sense according to lumbar angles in a flexion pattern (FP) subgroup of patients with non-specific chronic low back pain (NCSLBP). [Subjects] Thirteen subjects with FP low back pain participated. [Methods] The lumbar repositioning error (RE) of subjects was measured between a neutral starting position and re-position phases at three angles, in sitting and standing upright positions. [Results] Lumbar RE was significantly greater during lumbar flexion at a 30° angle in the sitting position than in the other tasks. [Conclusion] In the flexion-related subgroup, the lumbar RE measurement may be a more sensitive evaluation method using a lumbar flexion angle of 30° while in the sitting position, compared with other angles in sitting or standing positions.Key words: Flexion pattern, Low back pain, Repositioning error     

Rehabilitation training using a single-joint type hybrid assistive limb for the knee after anterior cruciate ligament reconstruction: an initial case report indicating safety and feasibility

[Purpose] The aim of this report was to describe the safety, feasibility, and efficacy of rehabilitation by knee extension and flexion training using the knee single-joint hybrid assistive limb in a patient after anterior cruciate ligament reconstruction. [Participant and Methods] A 33 year-old male underwent an arthroscopic procedure for anatomic single-bundle anterior cruciate ligament reconstruction with a semitendinosus tendon autograft. Rehabilitation training using the knee single-joint hybrid assistive limb was initiated at postoperative week 18 and repeated weekly for 3 weeks. The patient performed five sets of the knee single-joint hybrid assistive limb-assisted knee-extension-flexion exercises per session at a frequency of 10 exercises/set. [Results] The peak extension torque at all velocities with the limb symmetry index was higher after the hybrid assistive limb intervention (post-intervention) than before using it (pre-intervention). Peak flexion torques at 60°/s and 300°/s of limb symmetry index were higher post-intervention than pre-intervention. The range of motion in extension and flexion improved from −2° (pre-intervention) to −1° (post-intervention) and from 124° to 133°, respectively. The Lysholm score increased from 58 (pre-intervention) to 94 (post-intervention). [Conclusion] The knee single-joint hybrid assistive limb can be used safely for anterior cruciate ligament reconstruction training, without any adverse events. Our results indicate that the knee single-joint hybrid assistive limb training may improve muscle function, effectively overcoming dysfunction.Key words: The single-joint type hybrid assistive limb for the knee joint (knee HAL-SJ), Anterior cruciate ligament reconstruction, Muscle dysfunction     

Measuring seated hip extensor strength using a handheld dynamometer: an examination of the reliability and validity of the protocol

[Purpose] The purpose of this study was to examine the reliability and validity of measurements of hip extensor muscle strength using a handheld dynamometer (HHD) with subjects in a sitting position. In doing so, we also aimed to establish a modified method of measurement for patients with flexion contractures in the trunk and lower extremities. [Subjects and Methods] In 20 healthy males, hip extensor muscle strength was measured using a handheld dynamometer in sitting, prone, and standing positions by contracting the hip extensor muscle isometrically with the knee flexed at 90 degrees. For each position, we investigated the relative and absolute reliability and validity of the measurements, and compared muscle strength between the different positions. [Results] The reliability and validity of measurements were highest in the sitting position and higher in both the sitting and standing positions as compared with those in the prone position. [Conclusion] Our findings suggest that measurements taken in a sitting position are accurate in assessing hip extensor muscle strength and would be applicable to patients with flexion contractures in the trunk and lower extremities.Key words: Hip extensor strength, Reliability, Bland-Altman analysis     

Comparative Analysis of Acromiohumeral Distances According to the Locations of the Arms and Humeral Rotation

[Purpose] The purpose of this study was to compare the potential effects of resistance exercise according to the positions of the arms and the rotation of the humerus on the subhumeral acromial space. [Subjects] The study subjects were 34 subjects without shoulder pain. [Methods] Ultrasonographic measurements of the acromiohumeral distance of the subjects were made at three shoulder positions: 90° flexion, scaption at 90° abduction, and 90° abduction in an upright sitting position. The subjects were instructed to vertically push against a table to the maximum level with the humerus in internal, neutral, and external rotation. The measurements were made three times in each position. [Results] There was a significant difference in acromiohuneral distance between neutral and internal rotation of the humerus, and between external rotation and internal rotation of the humerus. In the scaption position, there was a significant difference between neutral and internal rotation of the humerus, and between external rotation and internal rotation of the humerus. In the 90° flexion position, there was a significant difference between neutral and internal rotation, and between neutral and external rotation. There was a significant difference between the flexion position and the abduction position, and between the flexion position and the scaption position. In terms of the internal rotation of the humerus, there was a significant difference between 90° flexion and 90° abduction. [Conclusion] These findings can be applied in exercises prescribed to increase the acromiohumeral distance and to aid the treatment and evaluation of shoulder dysfunctions.Key words: Ultrasonographic, Acromiohumeral distance, Humeral rotation     

Muscle activities of the rectus abdominis and rectus femoris and their ratio during leg raises performed by healthy adults

[Purpose] The purpose of this study was to analyze muscle activation during hip flexion in the supine position to examine the activation characteristics of the rectus abdominis and rectus femoris. [Subjects] The subjects of this study were 20 healthy adults (10 males and 10 females). [Methods] Muscle activities of the rectus abdominis and rectus femoris while raising the leg from 0°–60° were measured in 15-degree divisions and their ratio was calculated. [Results] Statistically significant differences were found in the muscle activities of the rectus femoris and rectus abdominis were found among each division of during hip flexion in the supine position. The rectus abdominis and rectus femoris ratios increased as the angle of hip flexion increased. [Conclusion] During hip flexion from 0°–45° in the supine position, femur motion caused hip flexion. At angles greater than or equal to 45° hip flexion was accompanied by pelvic motion.Key words: Hip flexion, Leg raise, Muscle activities     

Isokinetic Training Effect of Ankle Positions on Knee Extensor Strength

[Purpose] The purpose of this study was to determine which ankle position most influences knee extensor strength in training programs for strengthening the knee extensors using three different active ankle positions. [Subjects] Twenty-one healthy adults (6 males and 15 females) participated in this study. [Methods] Subjects were trained isokinetically in knee extension and flexion at 70 or 80% of 1RM under three actively and naturally fixed, contracted ankle conditions: dorsiflexion, plantarflexion, and resting position. After each group successfully executed the training four times a week for three weeks, mean peak torque (PT) and total work (TW) variables were measured and compared at 60°/sec and 180°/sec among the three groups. [Results] Significant differences were revealed in knee extensor TW at 60°/sec, PT and TW at 180°/sec, with the greatest PT and TW observed with the ankle in active dorsiflexion position. [Conclusion] These results suggest that active ankle dorsiflexion in a knee strength training program may be more effective at increasing knee extensor strength than a resting or plantarflexion position.Key words: Ankle position, Knee extensor strength, Isokinetic training     

Squat exercise to estimate knee megaprosthesis rehabilitation: a pilot study

[Purpose] This study evaluated a specific rehabilitation protocol using a half squat after total knee reconstruction with distal femur megaprosthesis and tibial allograft-prosthesis composite. [Subject and Methods] Squat execution was recorded by a three-dimensional system before and after a specific rehabilitation program on a 28-year-old patient. Squat duration, body center of mass trajectory, and vertical range of motion were determined. Step width and joint angles and symmetry (hip flexion, extension, and rotation, knee flexion, and ankle dorsal and plantar flexion) were estimated. Knee and hip joint symmetry was computed using a bilateral cyclogram technique. [Results] After rehabilitation, the squat duration was longer (75%), step width was similar, and vertical displacement was higher. Hip flexion increased by over 20%, and ankle dorsiflexion diminished by 14%. The knee had the highest symmetry gain (4.1–3.4%). Angle-angle plot subtended areas decreased from 108° to 40°² (hip) and from 204° to 85°² (knee), showing improvement in movement symmetry. [Conclusion] We concluded that the squat is an effective multifactorial exercise to estimate rehabilitation outcomes after megaprosthesis, also considering that compressive and shear forces are minimal up to 60–70° of knee flexion.Key words: Knee prosthesis, Half-squat, Knee ROM     

Effects of posture and lower limb muscle strength on the results of the Star Excursion Balance Test

[Purpose] This study aimed to clarify the relationship between the distance measurements in the Star Excursion Balance Test and participants’ posture and lower limb muscle strength. [Participants and Methods] Nine healthy male college students participated in this study. Star Excursion Balance Test distance was measured in both lower limbs by performing anterior, posterolateral, and posteromedial trials; measuring the maximum reach; and performing three-dimensional motion analysis to determine the posture at maximum reach. Isokinetic muscle strength for knee flexion/extension, hip flexion/extension, and hip adduction/abduction were measured using an isokinetic machine. [Results] The hip extension strength, reach side ankle dorsiflexion angles, stance side knee flexion, reach side knee flexion, and knee flexion strength were selected as significant explanatory variables in the anterior direction. For the posteromedial direction, hip adduction and hip extension strength, reach side hip flexion angle, and stance side hip flexion angle were selected. For the posterolateral direction, reach side knee flexion angle and stance side ankle dorsiflexion, knee flexion strength and reach side hip flexion angle were selected. [Conclusion] The related factors differed between the dominant and non-dominant legs even in the same reach direction.     

Changes in angular kinematics of the paretic lower limb at different orthotic angles of plantar flexion limitation of an ankle-foot-orthosis for stroke patients

[Purpose] An ankle-foot-orthosis (AFO) is an assistive brace that allows stroke patients to achieve an independent gait. Therefore, we examined whether or not the orthotic angle for plantar flexion limitation affects the kinematic parameters of the hip and knee joints on the affected side of patients with stroke. [Subjects and Methods] Fifteen patients with chronic hemiplegia were recruited for this study. Kinematic three-dimensional data was acquired, while patients walked along a walkway wearing AFOs under five different conditions of 0°, 5°, 10°, 15°, and 20° of plantar stop limitation angle in the orthotic joint. Peak angles of the hip and knee joints on the affected side were analyzed. [Results] At the peak angle of the knee joint, statistically significant differences were found only at mid-stance in the sagittal plane and the horizontal plane. However, no significant differences were observed among any of the orthotic limitation angles in the frontal plane. [Conclusion] According to the results, an orthotic limitation angle of more than 10° elicits changes in the knee joint angle at mid-stance in the sagittal and horizontal planes. This study provided basic data on postural changes of patients with stroke.Key words: Stroke, Ankle-foot-orthosis, Gait     

Effect of initial position on the muscle activity of the hip extensors and amount of pelvic tilt during prone hip extension

[Purpose] The aim of this study was to identify the effects of initial position of the hip joint with changes in the hip joint angle on the respective muscle activities of the bilateral erector spinae (ES), unilateral gluteus maximus (GM), and biceps femoris (BF) and the amount of pelvic anterior tilt during prone hip extension (PHE). [Subjects] Fifteen healthy volunteers were enrolled in this study. [Methods] The subjects performed PHE in three positions: neutral, 20°, and 45° flexed hip joint. The activities of the ES, GM, and BF were measured using surface electromyography, and kinematic values for pelvic anterior tilt were calculated using a motion capture system. [Results] There was a significant decrease in muscle activity of the contralateral ES at 45°, and an increase in the GM muscle activity and decrease in the BF muscle activity at 20°. The amount of pelvic anterior tilt was lower at 20°. [Conclusion] These results suggest that a hip flexion position of 20° would have an advantage over the other measured positions.Key words: Electromyography, Joint position, Prone hip extension     

Analysis of isokinetic muscle strength for sports physiotherapy research in Korean ssireum athletes

[Purpose] The purpose of the present study was to elucidate the muscle conditions such as the isokinetic muscle of Korean ssireum athletes. [Subjects and Methods] This study enrolled 25 elite ssireum athletes. We measured body composition and peak torque at an angular speed at 60°/s using an isokinetic muscle strength dynamometer. [Results] The lean body mass of the left upper limb was significantly higher than that of the right upper limb. However, the lean body mass of the left lower limb was significantly lower than that of the right lower limb. The peak torque for left elbow flexion was significantly higher than that for right elbow flexion. Conversely, the peak torque for left elbow extension was significantly lower than that for right elbow extension. Furthermore, the peak torque for the left knee was significantly lower than that for the right knee for both flexion and extension. [Conclusion] The data from this study elucidate in part the muscle conditions of Korean ssireum athletes, which can be used to establish a reference for the scientific study of sports physiotherapy.Key words: Isokinetic muscle strength, Ssireum athletes, Sports physiotherapy     

Comparison of the Plantar Pressure Distributions at Different Degrees of Tilting: A Preliminary Report

[Purpose] The purpose of this study was to investigate the amount of plantar pressures on the lower limb during tilt table standing and to indicate the ideal degree of tilting for partial weight bearing. [Subjects and Methods] Fifteen healthy subjects between the ages of 20 and 30 were recruited as volunteers for this study. All the measurements were taken while standing on a tilt table according to different inclination angles. [Results] The plantar pressures for 60° tilt table standing were lower by 7–9% of total body weight than the pressures during tilt table standing at 90°, and the pressures for 30° tilt table standing were lower by 18–20% of total body weight than the pressures for tilt table standing at 90°. [Conclusion] Standing training on a 60° tilt table might be equivalent to 80% of full weight bearing training, and tilt table standing training at 30° might be equivalent to 60% of full weight bearing training.Key words: Tilt table standing, Partial weight bearing, Standing training     

The kinematics of the lower leg in the sagittal plane during downward squatting in persons with pronated feet

[Purpose] This study aimed to examine changes in lower extremity kinematics in the sagittal plane during downward squatting by subjects with pronated feet. [Subjects and Methods] This study selected 10 subjects each with normal and pronated feet using a navicular drop test. The subjects performed downward squatting, in which the knee joints flex 90° in a standing position. We recorded the angles of the hip, knee, and ankle joint in the sagittal plane through motion analysis. For the analysis, the squatting phase was divided into phase 1 (initial squat), phase 2 (middle squat), and phase 3 (terminal squat) according to the timing of downward squatting. [Results] In the pronated foot group comparison with the normal group, the hip joint flexion angle decreased significantly in phases 2 and 3. The dorsiflexion angle of the ankle joint increased significantly in phase 3. The flexion angle of the knee joint did not differ between groups in any of the phases. [Conclusion] The pronated foot group utilized a different squat movement strategy from that of the normal foot group in the sagittal plane.Key words: Pronated foot, Kinematics, Squat     

Evaluation of the effects of different treatments for the elbow joint using joint proprioception and surface electromyography

[Purpose] The purpose of this study was to examine the immediate effects of strength training and neuromuscular joint facilitation (NJF) distal resistance training on muscle strength and proprioception. [Subjects] The subjects were 15 young healthy people (29.3±4.1 y, 166.8±7.1 cm, 62.4 ± 11.6 ky). [Methods] Two isometric contraction techniques were applied on the elbow joint: elbow joint flexion muscle strength training (MST) and the elbow joint flexion pattern of NJF. Muscle strength (measured by surface electromyography [sEMG]) and joint position errors of the left upper limb were measured before and after one intervention session of MST and NJF. [Results] The decrease in error in elbow flexion angle repetition represented the improvement resulting from NJF. sEMG of the biceps brachii showed significant increases in the maximum discharge and average discharge after the intervention. [Conclusion] This result suggests that elbow joint proprioception and muscle strength can be improved by NJF together with proximal resistance training.Key words: Neuromuscular joint facilitation, Joint position error, Elbow joint proprioception     

Knee joint movement and muscle activity changes in stroke hemiplegic patients on continuous use of knee-ankle-foot orthosis with adjustable knee joint

[Purpose] We aimed to evaluate knee joint movement and muscle activity ratio changes in stroke hemiplegic patients in recovery phase after using a knee-ankle-foot orthosis with an adjustable knee joint for 1 month; we also aimed to discuss the practical implications of our findings. [Participants and Methods] The participants were 8 hemiplegic patients in the recovery phase of stroke who were prescribed knee-ankle-foot orthosis with adjustable knee joint. We measured knee joint angles and electromyographic activity of the vastus medialis and biceps femoris during walking in two conditions: the knee-ankle-foot orthosis knee joint fixed in the extended position and the knee joint moved from 0° to 30° in the flexion direction. Measurements were taken 2 weeks after completion to account for habituation of the orthosis and repeated 1 month later. [Results] When the knee joint was moving from 0° to 30° in the flexion direction, the knee joint angle at initial contact and the minimum flexion angle of the gait cycle decreased significantly between the first and second measurements. When knee joint flexion was 30°, the muscle activity ratio of the vastus medialis increased significantly in the loading response and mid-stance compared to when it was fixed. [Conclusion] Setting the knee joint of a knee-ankle-foot orthosis in accordance with the knee joint movement may increase the muscle activity ratio of the vastus medialis from loading response to mid-stance.Key words: Stroke, Electromyography, Knee-ankle-foot orthosis     

THE IMPACT OF SAGITTAL PLANE HIP POSITION ON ISOMETRIC FORCE OF HIP EXTERNAL ROTATOR AND INTERNAL ROTATOR MUSCLES IN HEALTHY YOUNG ADULTS

Purpose/Background:

Hip external rotator (ER) and internal rotator (IR) muscle weakness is theorized to be associated with lower extremity injury in athletes including knee ligament tears and patellofemoral pain. Previous studies investigating hip musculature strength have utilized various sagittal plane hip positions for testing. The relationship between results at these different positions is unknown.

Methods:

Eighty healthy, pain‐free young adults participated in the study: 40 female, mean age 22.90 (± 2.32) years, and 40 male, mean age 23.50 (± 2.15) years. Peak isometric torque of bilateral hip ER and IR were tested at 90° and 0° of hip flexion with an instrumented dynamometer. Peak muscle forces were calculated. Peak forces were normalized by body mass. Mean normalized force was calculated for dominant and non‐dominant limbs for ER and IR in both positions. Male and female data were analyzed separately with paired t‐tests (2‐tailed). Reference values for average muscle force and torque were calculated for dominant and non‐dominant limbs for both hip positions.

Results:

Hip IR normalized peak force was greater at 90° compared to 0° flexion position bilaterally in both genders (p < .01). Hip ER normalized peak force was greater at 90° compared to 0° flexion in dominant limbs of both genders and in non‐dominant limbs of males (p < .01). Non‐dominant hip ER normalized force in females was greater at 90° versus 0° flexion; however, it was not significant (p = .092). Post hoc analysis of normalized average force (average over 5‐second contraction) yielded similar results.

Conclusion:

Clinicians and researchers should use consistent positioning for testing of hip ER and IR strength. This will improve certainty of determining if a patient’s strength has changed or if differences between groups are present. Reference values reported will be useful in order to determine if weakness is present and to set goals, particularly in cases of bilateral involvement.

Level of Evidence:

2b     

Treatment of scalene muscles with the Ergon technique can lead to greater improvement in hip abduction range of motion than local hip adductor treatment: a study on deep front line connectivity

[Purpose] This study aimed to investigate the effects of Ergon^® instrument-assisted softtissue mobilization of the upper and lower midpoints of the Deep Front Line (DFL) on hip abduction range of motion (ROM). [Participants and Methods] Forty healthy adults (29.3 ± 6.3 years; height: 175.8 ± 7.4 cm; weight: 77.2 ± 9.2 kg) were randomly divided into two groups and received a single 15-minute Ergon treatment in the upper midpoint (scalene muscles) and the lower midpoint of the DFL (hip adductors) on their dominant side. The non-dominant hip served as a control. Pre-and post-therapy active and passive hip abduction ROM at 0° and 90° flexion was examined using a goniometer. [Results] In both experimental groups, active and passive hip abduction ROM on the treated side improved significantly compared to the control side. Scalene treatment led to significantly greater improvement in active hip abduction ROM at 0° and 90° and in passive ROM at 90° compared to local hip adductor treatment. [Conclusion] The application of the Ergon technique on remote parts of the DFL may lead to a significant increase in hip abduction ROM compared to local hip adductors treatment.Key words: Hip, Deep Front Line, IASTM     

The Effects of Elbow Joint Angle Change on the Elbow Flexor Muscle Activation in Pulley with Weight Exercise

[Purpose] This research investigated the effect of angular variation of flexion of the elbow joint on the muscle activation of elbow flexor muscles. [Subjects] The research subjects were 24 male college students with a dominant right hand who had no surgical or neurological disorders and gave their prior written consent to participation with full knowledge of the method and purpose of this study. [Methods] The subjects'' shoulder joints stayed in the resting position, and the elbow joint was positioned at angles of 55°, 70°, and 90°. The angle between the pulley with weights and forearm stayed at 90°. Surface electromyography was used to measure muscle activities. Three measurements were made at each elbow angle, and every time the angle changed, two minutes rest was given. [Result] The muscle activities of the elbow flexors showed significant changes with change in the elbow joint angle, except for the biceps brachii activities between the angles of 55° and 70° of elbow flexion. The muscle activities of the biceps brachii and brachioradialis showed angle-related changes in the order of 55°, which showed the biggest value, followed by 70° and 90°. [Conclusion] In order to improve muscle strength of the elbow flexor using a pulley system, it seems more effective to have a 90° angle between the pulley with weights and the forearm when the muscle is stretched to a length 20% greater than its resting position.Key words: Pulley with weight exercise, Joint angle, Muscle activation