Comparison of hip extensor muscle activity including the adductor magnus during three prone hip extension exercises

Objectives: This study compared the role of the adductor magnus muscle (Amag) as a hip extensor while performing active prone hip extension (PHE), PHE with hip adduction (PHE-ADD), and PHE with hip abduction (PHE-ABD) with the gluteus maximus (Gmax) and hamstrings. Methods: The study recruited 22 healthy participants. Electromyography data were recorded from the Amag, Gmax, and medial and lateral hamstrings during PHE, PHE-ADD, and PHE-ABD. Normalized electromyographic data were examined using one-way, repeated-measures analyses of variance. Results: The magnitude of the Amag, Gmax, and hamstring activations did not differ significantly while performing PHE (p = 0.41). Furthermore, the Amag and hamstring activations were significantly greater than the Gmax activation when performing PHE-ADD (p < 0.05). The Gmax showed significantly greater activation during PHE-ABD than the Amag and medial and lateral hamstrings (p < 0.05). Conclusions: Based on these results, we advocate including the Amag as a hip extensor during the PHE test or exercise. Our preliminary results have the potential to be applied directly to the PHE test, for investigating the muscle-activation pattern of the Amag with the Gmax and hamstrings in patients with hip or lower back pain.     

Comparison of trunk and hip muscle activity during different degrees of lumbar and hip extension

[Purpose] This study compared the activity of trunk and hip muscles during different degrees of lumbar and hip extension. [Subjects] The study enrolled 18 participants. [Methods] Two exercises (hip and lumbar extension) and two ranges (180° and <180°) were studied. [Results] Differences in degree of extension affected the percentage maximal voluntary isometric contraction of the lumbar erector spinae and biceps femoris muscles, with significantly higher average values at >180° than at 180° lumbar extension. No significant differences were found in gluteus maximus activity according to exercise type or range. [Conclusion] Hip extension may be more effective and safer for lumbar rehabilitation than lumbar extension.Key words: EMG, Hip extension, Lumbar extension     

Comparison of gait before and after superficial trunk muscle exercise and deep trunk muscle exercise

[Purpose] The purpose of this study was to examine the effects of superficial trunk muscle and deep trunk muscle exercise on gait. [Subjects] The subjects were 45 young adults who voluntarily consented to participate. The subjects were divided into a control group, a superficial muscle exercise group, and a deep muscle exercise group with 15 participants in each group. [Methods] Each group performed the exercises 5 times a week for 4 weeks. A Gait Analyzer was used to measure the subjects’ gait. A one-way ANOVA was conducted for analysis between each group. [Results] After 4 weeks, the values from right heel contact to foot flat, left foot flat to heel off, right foot flat to heel off, and left heel off to toe off significantly differed among the groups. [Conclusion] The superficial trunk muscle exercise improved stability, such as the period of mid stance during gait. The deep trunk muscle exercise improved mobility, such as heel contact to foot flat and heel off to toe off during gait.Key words: Superficial trunk muscle exercise, Deep trunk muscle exercise, Gait     

The effects of isometric trunk exercises and dynamic trunk exercises on gait in elderly people

The purpose of this study was to compare the effects of dynamic trunk exercises and isometric trunk exercises on gait in elderly people. [Subjects] This study randomly allocated 20 elderly people to an isometric trunk exercise group (n=10) and a dynamic trunk exercise group (n=10). The exercises were performed for 30 minutes three times a week for 12 weeks. Gait speed, stride length, cadence, and step width were measured at a normal pace using GAITRite. All groups were evaluated before and after 12 weeks. [Results] The isometric exercise group showed a significant change in gait velocity, cadence, and left and right step lengths. The dynamic trunk exercise group showed a significant change in gait velocity, cadence, left and right step lengths, left and right step times, and left and right stride lengths. Moreover, a comparison of the exercise effect between the two groups showed a significant difference in gait velocity. [Conclusion] The results of this study suggest that isometric trunk exercises and dynamic trunk exercises have a positive effect on gait function in elderly people. In particular, isometric trunk exercises are recommended to promote gait velocity.Key words: Isometric trunk exercise, Dynamic trunk exercise, Gait     

Quantification of the differences in electromyographic activity magnitude between the upper and lower portions of the rectus abdominis muscle during selected trunk exercises

BACKGROUND AND PURPOSE: Controversy exists around exercises and clinical tests that attempt to differentially activate the upper or lower portions of the rectus abdominis muscle. The purpose of this study was to assess the activation of the upper and lower portions of the rectus abdominis muscle during a variety of abdominal muscle contractions. SUBJECTS: Subjects (N = 11) were selected from a university population for athletic ability and low subcutaneous fat to optimize electromyographic (EMG) signal collection. METHODS: Controlling for spine curvature, range of motion, and posture (and, therefore, muscle length), EMG activity of the external oblique muscle and upper and lower portions of rectus abdominis muscle was measured during the isometric portion of curl-ups, abdominal muscle lifts, leg raises, and restricted or attempted leg raises and curl-ups. A one-way repeated-measures analysis of variance was used to test for differences in activity between exercises in the external oblique and rectus abdominis muscles as well as between the portions of the rectus abdominis muscle. RESULTS: No differences in muscle activity were found between the upper and lower portions of the rectus abdominis muscle within and between exercises. External oblique muscle activity, however, showed differences between exercises. DISCUSSION AND CONCLUSION: Normalizing the EMG signal led the authors to believe that the differences between the portions of the rectus abdominis muscle are small and may lack clinical or therapeutic relevance.     

Effect of evidence-based trunk stability exercises on the thickness of the trunk muscles

[Purpose] This study was conducted to investigate the effect of four spine stability exercises on the thickness of the internal and external oblique abdominal muscles, the transverses abdominis, and the multifidus muscles. [Subjects and Methods] Forty healthy adults were enrolled and randomly allocated to four groups. Ten participants performed bridge exercises (BE) while lying on their back; 10 others performed the same exercises with their right legs up (BERL); another 10 performed the same exercises on their side (SBE); and the remaining 10 performed them in a quadruped position with left arm and right leg lifts (QLARL). The participants performed the exercises three times a week for five weeks. The thicknesses of the muscles before and after the interventions were measured using ultrasound. [Results] The results show that the normal bridge exercise significantly thickened the TrA; BERL, the LM; QLARL, the IO; and SBE, the EO and the IO. [Conclusion] All four spine stability exercises were effective. The normal bridge exercise and BERL selectively strengthened the local muscles at the early stage of the treatment. We consider SBE and QLARL should be used in the later stages of treatments because they strengthen both the local and global muscles.Key words: Trunk muscle thickness, Trunk stabilization, Ultrasonograpy     

Effects of flexi-bar and non-flexi-bar exercises on trunk muscles activity in different postures in healthy adults

[Purpose] The purpose of this study was to assess the effects of flexi-bar exercises and non-flexi-bar exercises on trunk muscle activity in different postures in healthy adults. [Subjects] Twenty healthy right-hand dominant adults (10 males and 10 females) were selected for this study. None of the participants had experienced any orthopedic problems in the spine or in the upper and lower extremities in the previous six months. [Methods] The subjects were instructed to adopt three exercise postures: posture 1, quadruped; posture 2, side-bridge; and posture 3, standing. Surface electromyography of selected trunk muscles was normalized to maximum voluntary isometric contraction. [Results] The external oblique, internal oblique, and erector spinae muscle activity showed significant differences between flexi-bar exercises and non-flexi-bar exercises. [Conclusion] The results of this study suggest that flexi-bar exercises are useful in the activation of trunk muscles.Key words: Flexi-bar, Vibration, Electromyography     

Effects of selective exercise for the deep abdominal muscles and lumbar stabilization exercise on the thickness of the transversus abdominis and postural maintenance

[Purpose] The purpose of this study was to examine the effects of selective exercise for the deep abdominal muscles (SEDA) and lumbar stabilization exercise (LSE) on the thickness of the transversus abdominis and postural maintenance on an unstable base of support. [Subjects and Methods] The subjects of this study were 20 male and 10 female adults in their 20s without lumbar pain. They were equally and randomly assigned to a SEDA group and a LSE group. The thickness of the transversus abdominis was measured using ultrasound imaging during rest and drawing-in. The thickness of the transversus abdominis was measured when subjects raised their right and left legs while lying on a Swiss ball. [Results] Initially, there were no differences between the two groups. After the intervention, significant differences were observed in all parameters. A significant interaction between group and period was not found for any parameters. [Conclusion] In conclusion, both SEDA and LSE thickened the transversus abdominis, which is a deep abdominal muscle, thereby adjusting posture, and stabilizing the trunk. These exercises increased the thickness of the deep abdominal muscles. They are important exercises for improving the stability of athletes or patients who need postural adjustment.Key words: Transversus abdominis, Selective exercise, Lumbar stabilization     

Comparison of the electromyographic activity of the tibialis anterior and gastrocnemius in stroke patients and healthy subjects during squat exercise

[Purpose] The purpose of this study was to compare the EMG activity of the tibialis anterior (TA) and gastrocnemius (GCM) during the downward, maintenance, and upward phases of the squat exercise and during passive ankle dorsiflexion range of motion between stroke patients and healthy subjects. [Subjects] Fifteen hemiplegic (8 males, 7 females) and 15 healthy subjects (4 males, 11 females) volunteered for this study. [Methods] All subjects performed a double-leg squat exercise with the knee joint flexed to 30°. Surface electromyography (EMG) signals were recorded from the TA and GCM on the paretic or nondominant side. Passive ankle dorsiflexion range of motion (DF PROM) was measured using a goniometer in the knee-extended prone position. [Results] In the downward and maintenance phases, TA activity was significantly higher in stroke patients compared with healthy subjects. In the upward phase, GCM activity was significantly lower in stroke patients compared with healthy subjects. Ankle DF PROM was significantly lower in stroke patients compared with healthy subjects. [Conclusion] The observed EMG patterns should be taken into consideration to inform and enhance therapy for stroke patients.Key words: EMG, Squat exercise, Stroke     

The effect of superficial trunk muscle exercise and deep trunk muscle exercise on the foot pressure of healthy adults

[Purpose] The purpose of this study was to analyze the effect of superficial trunk muscle exercise and deep trunk muscle exercise on the foot pressure of healthy adults. [Subjects] The subjects were 30 healthy females and males who agreed to participate in this study. There were two groups, a superficial trunk muscle exercise group and a deep trunk muscle exercise group, with 15 participants in each. [Methods] The exercises were conducted 5 times a week for 4 weeks for both groups. A gait analyzer was used to measure foot plantar pressure while walking on a plate. Participants were measured before starting the exercise and after 4 weeks. The paired t-test was used to analyze the pre-and post-test results. [Results] There were no significant differences in foot pressure in any region in the superficial trunk muscle exercise group. In the deep trunk muscle exercise group, there were statistically significant increase in F1, F4, F5, R1 and R3. In addition, there were significant decreases in R2 and R4. [Conclusion] After the 4-week deep trunk muscle exercise group decreases in foot pressure on the inner foot and increases on the outside of the feet indicate normal and overall even distribution of body weight on the feet.Key words: Superficial trunk muscle exercise, Deep trunk muscle exercise, Foot pressure     

Comparison of the isolated contraction ratios of the hip extensors and erector spinae muscles of the lumbar region and thoracic muscles during different back extension exercises

[Purpose] This study compared the isolated contraction ratios of the hip extensors, erector spinae muscles of the lumbar region, and thoracic muscles during different back extension exercises. [Subjects] Twelve males participated in this study. [Methods] The subjects performed various back extension exercises. The activities of the T7 erector spinae muscles, L3 erector spinae muscles, and the gluteus maximus were measured, and the isolation contraction ratios were calculated. [Results] The isolated contraction ratio of the T7 erector spinae muscles significantly increased during exercise 2. The isolated contraction ratio of the gluteus maximus increased by a significant degree during exercise 1 compared with the other exercises. [Conclusion] This study demonstrated that the back extension exercises 1 and 2 can be applied to selectively exercise the hip extensors, thoracic muscles, and muscles of the lumbar region.Key words: Back extensor, Isolated contraction ratio, Selected exercise     

Relationship between knee alignment and the electromyographic activity of quadriceps muscles in patients with knee osteoarthritis

[Purpose] We evaluated the relationship between knee alignment and the electromyographic (EMG) activity of the vastus medialis (VM) to the vastus lateralis (VL) muscles in patients with knee osteoarthritis (OA) in a cross-sectional study. [Subjects and Methods] Forty subjects with knee OA were assessed by anatomic radiographic knee alignment and the VM/VL ratio was calculated. Surface EMG from both the VM and VL muscles were evaluated during maximal isometric contraction at 60° knee flexion. Simultaneously, peak quadriceps torque was assessed using an isokinetic dynamometer. Subjects were categorized into low, moderate, and high varus groups according to knee malalignment. The peak quadriceps torque and VM/VL ratio across groups, and their relationships with varus malalignment were analyzed. [Results] All subjects had medial compartment OA and the VM/VL ratio of all subjects was 1.31 ± 0.28 (mean ± SD). There were no significant differences in the peak quadriceps torque or VM/VL ratios across the groups nor were there any significant relationships with varus malalignment. [Conclusion] The VM/VL ratio and peak quadriceps torque were not associated with the severity of knee varus malalignment.Key words: Malalignment, Knee, Quadriceps     

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     

The effects of horseback riding simulator exercises on the muscle activity of the lower extremities according to changes in arm posture

[Purpose] This study aimed to determine the effects of horseback riding simulator exercise on the muscle activities of the lower extremities according to changes in arm posture. [Subjects] The subjects of this study were 30 normal adult males and females. [Methods] The horseback riding simulator exercise used a horseback riding simulator device; two arm postures were used, posture 1 (holding the handle of the device) and posture 2 (crossing both arms, with both hands on the shoulders). Electromyography was used to compare the muscle activities of the rectus femoris, biceps femoris, and hip adductors in the lower extremities. [Results] Posture 2 had significantly higher muscle activity than posture 1. [Conclusion] Posture 2, which entailed crossing both arms with both hands on the shoulders, was an effective intervention for improved muscle activity in the hip adductors.Key words: Horseback riding simulator exercise, Muscle activity, Arm posture     

Electromyographic analysis of trunk and lower extremity muscle activities during pulley-based shoulder exercises performed on stable and unstable surfaces

[Purpose] The aim of the present study was to identify the effects of an unstable support surface (USS) on the activities of trunk and lower extremity muscles during pulley-based shoulder exercise (PBSE). [Subjects] Twenty healthy college students were included in this study. [Methods] Surface EMG was carried out in twenty healthy adult men. The activities of trunk and lower extremity muscles performed during PBSE using a resistance of 14 kg on a stable or unstable support surface were compared. The PBSE included shoulder abduction, adduction, flexion, extension, internal rotation, and external rotation. [Results] On the unstable surface, the rectus abdominis and erector spinae showed significantly less activation during shoulder external rotation, but the extent of activation was not significantly different during other shoulder exercises. The external oblique and rectus femoris showed no significant difference during any shoulder exercises. The tibialis anterior showed significantly greater activation during all shoulder exercises, except flexion and extension. The gastrocnemius showed significantly greater activation during shoulder abduction, extension, and internal rotation. However, during shoulder adduction, flexion, and external rotation, the gastrocnemius showed no significant difference. [Conclusion] The use of USS to increase core stability during PBSE is probably not effective owing to compensatory strategies of the ankle.Key words: Electromyography, Core stability, Ankle strategy     

Effects of external pelvic compression on trunk and hip muscle EMG activity during prone hip extension in females with chronic low back pain

Many studies have reported higher trunk and hip muscle activity in patients with chronic low back pain (CLBP). Increased trunk and hip muscle activity could contribute to pain. Previous studies have shown that external pelvic compression (EPC) decreased back and hip muscle activity during physical tasks.In this study, we assessed the effects of EPC on the electromyography (EMG) activity of the latissimus dorsi (LD), elector spinae (ES), gluteus maximus (GM), and biceps femoris (BF) in a CLBP group and a healthy group during prone hip extension (PHE).Forty female volunteers (20 non-specific CLBP, 20 healthy) were recruited. Surface EMG data were collected from the LD, ES, GM, and BF muscles during a PHE task. Normalized EMG values were analyzed by separate repeated-measures analysis of variance (ANOVA) for each muscle.The normalized EMG activity in the left LD, bilateral ES, and right GM was significantly higher in the CLBP group than in the healthy group during PHE. In the CLBP group, the normalized EMG activity in the left LD, bilateral ES, and right GM was significantly lower with EPC than without (p < 0.05). This suggests that the application of EPC decreased trunk and hip extensor EMG activity in the CLBP group during PHE.     

Comparison of foot pressure in stretching exercises according to the type of ankle ramp

[Purpose] This study compared and analyzed use of an existing ankle ramp and a newly developed ankle ramp for stretching exercises. [Subjects] Fourteen subjects were included; they were stroke patients more than 6 months after onset, with no orthopedic or biological problems in the legs, so independent gait was possible. [Methods] The subjects performed stretching exercises for 5 min with an existing ankle ramp and a newly developed ankle ramp; foot pressure was then measured. [Results] The averaged percentage and kilopascal data for weight bearing and foot pressure on the affected side with the newly developed ankle ramp for stretching exercises were significantly higher than those with the existing ankle ramp. [Conclusion] Our results suggest that stretching exercises using the newly developed ankle ramp more effectively increase foot pressure than the existing ankle ramp.Key words: Ankle ramp, Foot pressure, Stroke     

Comparison of ankle plantar flexor activity between double-leg heel raise and walking

[Purpose] We aimed to evaluate the difference in the muscle activity between the double-leg heel raise (DHR) and treadmill walking. [Subjects] Thirty healthy males aged 21.5 ± 1.6 years (body mass 63.6 ± 9.3 kg, height 171.0 ± 4.5 cm) participated in the study. [Methods] Electromyograms were simultaneously recorded from both heads of the gastrocnemius and the soleus of the right side during the DHR and treadmill walking. The DHR conditions were maximum plantar flexion (MPF), 3/4 MPF, 2/4 MPF, and 1/4 MPF, and the walking speeds were 20, 40, 60, 80, and 100 m/min. [Results] The muscle activity during the DHR and walking significantly increased with increments in the height of the heel raise and walking speed, respectively. Comparison of the muscle activity at MPF with that at each walking speed revealed that the muscle activity in the soleus and gastrocnemius medial head during walking exceeded that during the DHR in less than 3.3% of cases. [Conclusion] The DHR test is useful for evaluating the ankle plantar flexor activity necessary for walking.Key words: Double-leg heel raise, Walking, Plantar flexor