Influence of scapular motion cues on trapezius muscle activity during Y exercise.

BACKGROUND: The Y exercise is a therapeutic exercise facilitating lower trapezius muscle activity. OBJECTIVE: To identify the effects of scapular movement cues (posterior tilt vs. posterior tilt with adduction/depression) on trapezius muscle activity during Y exercise. METHODS: Fifteen healthy men without current shoulder pain performed general Y exercise; Y exercise with cues for scapular posterior tilt; and Y exercise with cues for scapular posterior tilt, adduction, and depression. Electromyography (EMG) data for the trapezius muscles were collected during Y exercise. The posterior tilt angle of the scapula was measured in the prone position with and without cues for scapular posterior tilt using an inclinometer application. RESULTS: The greatest lower trapezius muscle activity was observed during Y exercise with cues for scapular posterior tilt, while the greatest EMG activity of the upper trapezius was observed during Y exercise with cues for scapular posterior tilt, adduction, and depression (p< 0.05). Middle trapezius muscle activity did not significantly differ among the three Y exercise conditions (p= 0.175). Cues for scapular posterior tilt significantly increased the scapular posterior tilt angle in the prone shoulder abduction position (p= 0.007). CONCLUSION: Cues for scapular posterior tilt were most effective in facilitating lower trapezius muscle activity during Y exercise.

Effects of the abdominal drawing-in maneuver on hamstring rotational activity and pelvic stability in females.

BACKGROUND: The medial hamstring (MH) and lateral hamstring (LH) can be selectively trained through tibial internal and external rotation during prone knee flexion. However, no study has identified how a combined tibial rotation and lumbo-pelvic stability strategy influences MH and LH muscle activities. OBJECTIVE: To investigate the combined effects of tibial rotation and the abdominal drawing-in maneuver (ADIM) on MH and LH muscle activities as well as pelvic rotation during prone knee flexion. METHODS: Fifteen female volunteers performed prone knee flexion with tibial internal and external rotation, with and without the ADIM. Under each condition, MH and LH muscle activities were measured by surface electromyography (EMG), and the pelvic rotation angle by a smartphone inclinometer application. RESULTS: The results showed increased MH (without the ADIM: p< 0.001, effect size (d) = 2.05; with the ADIM: p< 0.001, d= 1.71) and LH (without the ADIM: p< 0.001, d= 1.64; with the ADIM: p= 0.001, d= 1.58) muscle activities under internal and external tibial rotation, respectively. However, addition of the ADIM led to increased MH (internal tibial rotation: p= 0.001, d= 0.67; external tibial rotation: p= 0.019, d= 0.45) and LH (internal tibial rotation: p= 0.003, d= 0.79; external tibial rotation: p< 0.001, d= 1.05) muscle activities combined with reduced pelvic rotation (internal tibial rotation: p< 0.001, d= 3.45; external tibial rotation: p< 0.001, d= 3.01) during prone knee flexion. CONCLUSIONS: These findings suggest that the ADIM could be useful for reducing compensatory pelvic rotation and enhancing selective muscle activation in the MH and LH, according to the direction of tibial rotation, during prone knee flexion.

Effects of Intended Scapular Posterior Tilt Motion on Trapezius Muscle Electromyography Activity.

The intended scapular motion is a strategy to strengthen the lower trapezius (LT). However, few studies have explored the effects of the intended scapular posterior tilt motion on selective LT activation. Thus, the present study investigated the effect of the intended scapular posterior tilt on the electromyography (EMG) activity of trapezius muscles during prone shoulder horizontal abduction (PSHA). Eighteen asymptomatic men performed three types of PSHA: (1) preferred PSHA, (2) PSHA with the intended scapular posterior tilt, and (3) PSHA with the intended scapular posterior tilt and trunk extension. EMG activity of the upper trapezius (UT), middle trapezius (MT), and LT were measured during PSHAs. Scapular posterior tilt angle, with and without the intended scapular posterior tilt, were measured using inclinometer. The results indicated that LT muscle activity increased when scapular posterior tilt was applied with and without trunk extension (14-16%), compared to the preferred condition, during PSHA (p < 0.05). However, the addition of trunk extension to PSHA with the intended scapular posterior tilt increased the UT muscle activity (28%) and the UT/LT (29%) and UT/MT (31%) ratios (p < 0.05). The scapular posterior tilt angle was higher (15%) when applying the intended scapular posterior tilt (p = 0.020). These findings suggest that the intended scapular posterior tilt may be a useful strategy for selective LT muscle activation.

Effects of Visual Biofeedback on Symmetrical Movements During Bridge Exercise With Sling.

CONTEXT: Asymmetrical movements of trunk and lower-extremity are common during the bridge exercise on the unstable condition. However, no studies have investigated whether visual biofeedback of pressing pressure on the unstable surface changes muscle activation patterns of trunk and hip extensors and pelvic rotation during the bridge exercise. OBJECTIVE: To investigate how visual biofeedback of pressing pressure influences symmetrical activity of lumbar and hip extensor and pelvic rotation. DESIGN: Cross-sectional study. SETTING: Laboratory. PARTICIPANTS: Twenty healthy males participated in this study. INTERVENTIONS: The participants performed 2 versions of the bridge exercise: the standard bridge exercise and the bridge exercise with visual biofeedback using amount of pressing pressure on the sling. MAIN OUTCOME MEASURES: Surface electromyography was used to measure the symmetry (ie, the difference between dominant and nondominant sides) of muscle activation in the bilateral erector spinae, gluteus maximus, and hamstring muscles, and motion sensors were used to assess pelvic rotation. Symmetry of pressing pressure was measured using a tension meter. RESULTS: The differences between the dominant and nondominant pressing pressures and differences between the electromyography activity of the dominant and nondominant erector spinae, gluteus maximus, and hamstring were significantly smaller during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05). In addition, there was significantly less pelvic rotation during the bridge exercise with visual biofeedback than during the standard bridge exercise (P < .05). CONCLUSIONS: The present findings suggest that visual biofeedback strategy may be a useful method for enhancing the symmetrical activation of the erector spinae, gluteus maximus, and hamstring and for reducing pelvic rotation during the bridge exercise on the unstable surface.

Strategies for controlling axial shoulder rotation change shoulder muscle activity during external rotation exercises.

BACKGROUND: The infraspinatus muscle has a crucial role in shoulder stability. Although axial shoulder rotation is useful for selective activation of the infraspinatus, no study has examined the influence of exercise position on axial shoulder rotation during shoulder external rotation (ER) exercises. Thus, this study investigated the muscle activity in the infraspinatus, posterior deltoid, and middle trapezius during shoulder ER exercises performed with and without controlled axial shoulder rotation in 2 different positions. METHODS: Twenty healthy subjects performed prone external rotation (PER) exercises with and without pressure biofeedback and seated external rotation (SITER) exercises with and without posterior humeral head gliding. Muscle activity during each ER exercise was measured using surface electromyography. RESULTS: Exercise strategy (P < .001) and position (P < .001) had a significant main effect on muscle activity in the infraspinatus and posterior deltoid. However, no significant interaction between strategy and position was observed. For muscle activity in the middle trapezius, strategy and position had a significant interaction effect (P = .014). Muscle activity in the infraspinatus increased significantly with the use of strategies to control axial shoulder rotation, whereas muscle activity in the posterior deltoid and middle trapezius decreased significantly. For all 3 muscles, greater activity was observed in the prone position than the seated position. CONCLUSION: We suggest that PER with pressure biofeedback can be useful to improve selective activation of the infraspinatus muscle while further eliciting infraspinatus muscle activity.

Effects of self-stretching with mobilization on shoulder range of motion in individuals with glenohumeral internal rotation deficits: a randomized controlled trial.

BACKGROUND: The combined effects of cross-body stretching and dorsal glide mobilization have not been examined previously, although both stretching and mobilization maneuvers are effective for improving shoulder range of motion (ROM). Thus, the aim of this study was to demonstrate the effects of stretching with mobilization (SWM) on glenohumeral (GH) internal rotation (IR) and horizontal adduction (HA) ROM. METHODS: Forty individuals with GH IR deficits were randomized to perform simultaneous combined cross-body stretching and dorsal glide mobilization (SWM group, comprising 10 male and 10 female patients) or cross-body stretching alone (stretching group, comprising 10 male and 10 female patients). GH IR ROM, HA ROM, and shoulder mobility were assessed before and immediately following interventions. Group and time differences were analyzed using 2-way repeated-measures analysis of variance. RESULTS: Greater changes in GH IR ROM (6°, P < .001), HA ROM (10°, P < .001), and shoulder mobility (-2 cm, P = .018) were observed in the SWM group than in the stretching group, although significant increases were observed in GH IR ROM (SWM group, P < .001; stretching group, P < .001), HA ROM (SWM group, P < .001; stretching group, P = .042), and shoulder mobility (SWM group, P < .001; stretching group, P < .001) after both interventions. CONCLUSION: This study shows that SWM could be a useful exercise for shoulder ROM recovery in individuals with GH IR deficits.

Effects of real-time visual biofeedback of pelvic movement on electromyographic activity of hip muscles and lateral pelvic tilt during unilateral weight-bearing and side-lying hip abduction exercises.

Although neutral pelvic alignment is important for hip abduction exercises, studies exploring objectively monitored pelvic alignment on the gluteus medius (Gmed) muscle activity during hip abduction exercises, especially under weight-bearing (WB) conditions, are limited. Therefore, we examined the effects of real-time visual biofeedback (RVBF) of pelvic movement on electromyographic (EMG) activity of hip muscles and lateral pelvic tilt during unilateral WB and side-lying hip abductions. Fifteen male participants performed unilateral WB and side-lying hip abduction exercises with and without RVBF. Under the RVBF condition, participants monitored pelvic movements in real time during hip abduction exercises. EMG activity of Gmed and quadratus lumborum (QL) as well as lateral pelvic tilt angle were recorded during each hip abduction exercise. Gmed EMG activity increased, while lateral pelvic tilt decreased during both hip abduction exercises with RVBF (p < 0.05). Additionally, the changes in Gmed activity, the Gmed/QL activity ratio, and the lateral pelvic tilt angle under RVBF were greater during unilateral WB hip abduction than during side-lying hip abduction (p < 0.05). These results suggest that RVBF of pelvic movement could be useful to strengthen Gmed and prevent compensatory lateral pelvic movement during hip abduction exercises, especially in the unilateral WB position.

Influence of ankle dorsiflexion range of motion on heel-rise time during gait.

[Purpose] The purpose of this study was to examine the correlation between weight-bearing (WB) and non-WB ankle dorsiflexion (DF) range of motion (ROM) and ankle movement during gait, including heel-rise time and ankle DF at heel-rise. [Subjects and Methods] Thirty healthy male subjects were recruited for this study. Ankle DF ROM of both feet was measured under the WB and non-WB conditions. Heel-rise time and ankle DF at heel-rise in both feet during gait were measured using a motion analysis system. Pearson product moment correlations were used to identify correlation ankle DF ROM and ankle movement during gait. [Results] Heel-rise time and ankle DF at heel rise were significantly correlated with WB ankle DF ROM. However, no correlations were found between ankle movement during gait and non-WB ankle DF ROM. [Conclusion] These findings demonstrate that WB ankle DF ROM measurements can be used to predict heel-rise time and ankle DF at heel-rise.

Effect of modified bridge exercise on trunk muscle activity in healthy adults: a cross sectional study.

DESIGN: This is a cross-sectional study. SETTING: University research laboratory. PARTICIPANTS: Fifteen healthy adults (mean age: 27.47 years) volunteered for this study. INTERVENTION: The individuals performed standard bridge exercise and modified bridge exercises with right leg-lift (single-leg-lift bridge exercise, single-leg-lift bridge exercise on an unstable surface, and single-leg-lift hip abduction bridge exercise). MAIN OUTCOME MEASURES: During the bridge exercises, electromyography of the rectus abdominis, internal oblique, erector spinae, and multifidus muscles was recorded using a wireless surface electromyography system. Two-way repeated-measures analysis of variance (exercise by side) with post hoc pairwise comparisons using Bonferroni correction was used to compare the electromyography data collected from each muscle. RESULTS: Bilateral internal oblique muscle activities showed significantly greater during single-leg-lift bridge exercise (95% confidence interval: right internal oblique=-8.99 to -1.08, left internal oblique=-6.84 to -0.10), single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right internal oblique=-7.32 to -1.78, left internal oblique=-5.34 to -0.99), and single-leg-lift hip abduction bridge exercise (95% confidence interval: right internal oblique=-17.13 to -0.89, left internal oblique=-8.56 to -0.60) compared with standard bridge exercise. Bilateral rectus abdominis showed greater electromyography activity during single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right rectus abdominis=-9.33 to -1.13, left rectus abdominis=-4.80 to -0.64) and single-leg-lift hip abduction bridge exercise (95% confidence interval: right rectus abdominis=-14.12 to -1.84, left rectus abdominis=-6.68 to -0.16) compared with standard bridge exercise. In addition, the right rectus abdominis muscle activity was greater during single-leg-lift hip abduction bridge exercise compared with single-leg-lift bridge exercise on an unstable surface (95% confidence interval=-7.51 to -0.89). For erector spinae, muscle activity was greater in right side compared with left side during all exercises (95% confidence interval: standard bridge exercise=0.19-4.53, single-leg-lift bridge exercise=0.24-10.49, single-leg-lift bridge exercise on an unstable surface=0.74-8.55, single-leg-lift hip abduction bridge exercise=0.47-11.43). There was no significant interaction and main effect for multifidus. CONCLUSIONS: Adding hip abduction and unstable conditions to bridge exercises may be useful strategy to facilitate the co-activation of trunk muscles.

Relationship Between Weightbearing Ankle Dorsiflexion Passive Range of Motion and Ankle Kinematics During Gait.

BACKGROUND: Measurement of weightbearing ankle dorsiflexion (DF) passive range of motion (PROM) has been suggested as a way to estimate ankle kinematics during gait; however, no previous study has demonstrated the relationship between ankle DF during gait and ankle DF PROM with knee extension. We examine the relationship between maximum ankle DF during gait and nonweightbearing and weightbearing ankle DF PROM with knee extension. METHODS: Forty physically active individuals (mean ± SD age, 21.63 ± 1.73 years) participated in this study. Ankle DF PROM with knee extension was measured in the nonweightbearing and weightbearing conditions; maximum ankle DF during gait was assessed using a three-dimensional motion analysis system. The relationship between each variable was calculated using the Pearson product moment correlation coefficient, and the difference in ankle DF PROM between the nonweightbearing and weightbearing conditions was analyzed using a paired t test. RESULTS: The weightbearing measurement (r = 0.521; P < .001) for ankle DF PROM showed a greater correlation with maximum ankle DF during gait than did the nonweightbearing measurement (r = 0.245; P = .029). Ankle DF PROM was significantly greater in the weightbearing than in the nonweightbearing condition (P < .001) despite a significant correlation between the two measurements (r = 0.402; P < .001). CONCLUSIONS: These findings indicate that nonweightbearing and weightbearing measurements of ankle DF PROM with knee extension should not be used interchangeably and that weightbearing ankle DF PROM with the knee extended is more appropriate for estimating ankle DF during gait.

Effects of spring-loaded crutches on gastrocnemius activity and upward displacement of the body during gait.

[Purpose] This study investigated the effects of spring-loaded crutches on gastrocnemius muscle activity and upper body displacement in the sagittal plane during gait. [Subjects and Methods] The study involved 12 healthy males. All subjects performed crutch gait by using spring-loaded crutches and axillary crutches. During this gait, the gastrocnemius muscle activity was measured using a wireless electromyography system, and upward displacement of the body was measured using a three-dimensional motion analysis system. [Results] The gastrocnemius activity was significantly lower but upward displacement of the body was significantly greater with the spring-loaded crutches than with axillary crutches. [Conclusion] Spring-loaded crutches allow efficient crutch gait and involve less effort from the gastrocnemius muscle.

Effects of isometric hip movements on electromyographic activities of the trunk muscles during plank exercises.

[Purpose] The purpose of this study was to investigate the effect of isometric hip adduction and abduction on trunk muscle activity during plank exercises. [Subjects and Methods] Nineteen healthy male subjects were recruited for this study. All subjects performed the traditional plank exercise (TP), plank exercise with isometric hip adduction (PHAD), and plank exercise with isometric hip abduction (PHAB) by using an elastic band. Electromyographic (EMG) activities of the internal oblique (IO) and external oblique (EO) were measured during the 3 plank exercises by using an Electromyography system. [Results] Internal oblique and external oblique muscle activities were significantly greater during plank exercise with isometric hip adduction and plank exercise with isometric hip abduction than during traditional plank exercise. Internal oblique and external oblique muscle activities did not differ between the plank exercise with isometric hip adduction and plank exercise with isometric hip abduction conditions. [Conclusion] These findings demonstrate that loaded isometric hip movements may be a useful strategy to increase trunk muscle activity during plank exercises.

Differences in performance on the functional movement screen between chronic low back pain patients and healthy control subjects.

[Purpose] Differences in scores on the Functional Movement Screen between patients with chronic lower back pain and healthy control subjects were investigated. [Subjects and Methods] In all, 20 chronic lower back pain patients and 20 healthy control subjects were recruited. Chronic lower back pain patients and healthy controls performed the Functional Movement Screen (deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability pushup, and rotary stability). The Mann-Whitney test was used to analyze differences in Functional Movement Screen scores between the two groups. [Results] Chronic lower back pain patients scored lower on the Functional Movement Screen total composite compared with healthy control subjects. Chronic lower back pain patients scored lower on Functional Movement Screen subtests including the deep squat, hurdle step, active straight leg raise, and rotary stability tests. [Conclusion] The deep squat, hurdle step, active straight leg raise, and rotary stability tasks of the Functional Movement Screen can be recommended as a functional assessment tools to identify functional deficits in chronic lower back pain patients.

Reproducibility of isometric shoulder protraction and retraction strength measurements in normal subjects and individuals with winged scapula.

BACKGROUND: The strength of the shoulder protractors and retractors may be compromised in individuals with winged scapula (IwWS). However, no standard approach to measuring the strength of these muscles has been described. The aim of this study was to study the intra-rater and inter-rater reproducibility of a fixed-base isometric dynamometer and to describe cutoff scores for clinically meaningful change for protraction and retraction isometric strength. METHOD: Twice during a week, 20 normal subjects and 20 IwWS were tested by 2 independent raters. RESULTS: IwWS were significantly weaker (P < .001) than control subjects in their protraction and retraction isometric strength. Excellent intra-rater and inter-rater correlations were obtained in most combinations, leading to low cutoff scores for meaningful change expressed in terms of the smallest real difference. CONCLUSION: When it is properly used, the technique described in this paper is recommended as an effective clinical tool for the quantitative assessment of protraction and retraction isometric strength, both for status determination and for monitoring of change in IwWS during and after rehabilitation.

Comparison of EMG activity on abdominal muscles during plank exercise with unilateral and bilateral additional isometric hip adduction.

The aim of this study was to investigate the effects of additional isometric hip adduction during the plank exercise on the abdominal muscles. Twenty healthy young men participated in this study. Surface electromyography (EMG) was used to monitor the activity of the bilateral rectus abdominis (RA), the internal oblique (IO), and the external oblique (EO) muscles. The participants performed three types of plank exercise; the standard plank exercise, the plank exercise with bilateral isometric hip adduction, and the plank exercise with unilateral isometric hip adduction. All abdominal muscle activity was significantly increased during the plank exercise combined with the bilateral and unilateral isometric hip adduction compared with the standard plank exercise (p<0.05). Bilateral IO, EO, and left RA muscle activity was significantly increased during the unilateral isometric hip adduction compared with the bilateral isometric hip adduction (p<0.05). These findings suggest that additional isometric hip adduction during the plank exercise could be a useful method to enhance abdominal muscle activity. In particular, the unilateral isometric hip adduction is a more beneficial exercise than the bilateral isometric hip adduction.

Is there an agreement among the items of the Korean physical therapist licensing examination, learning objectives of class subjects, and physical therapists' job descriptions?

PURPOSE: To determine the agreement among the items of the Korean physical therapist licensing examination, learning objectives of class subjects, and physical therapists' job descriptions. METHODS: The main tasks of physical therapists were classified, and university courses related to the main tasks were also classified. Frequency analysis was used to determine the proportions of credits for the classified courses out of the total credits of major subjects, exam items related to the classified courses out of the total number of exam items, and universities that offer courses related to the Korean physical therapist licensing examination among the surveyed universities. RESULTS: The proportions of credits for clinical decision making and physical therapy diagnosis-related courses out of the total number credits for major subjects at universities were relatively low (2.06% and 2.58%, respectively). Although the main tasks of physical therapists are related to diagnosis and evaluation, the proportion of physiotherapy intervention-related items (35%) was higher than that of examination and evaluation-related items (25%) on the Korean physical therapist licensing examination. The percentages of universities that offer physical therapy diagnosis and clinical decision making-related courses were 58.62% and 68.97%, respectively. CONCLUSION: Both the proportion of physiotherapy diagnosis and evaluation-related items on the Korean physical therapist licensing examination, and the number of subjects related to clinical decision making and physical therapy diagnosis in the physical therapy curriculum, should be increased to ensure that the examination items and physical therapy curriculum reflect the practical tasks of physical therapists.

The effects of gait with use of smartphone on repositioning error and curvature of the lumbar spine.

[Purpose] This study evaluated the effect of smartphone use on lumbar spine repositioning error and lumbar curvature while walking on a treadmill. [Subjects] A total of 20 healthy individuals (18 males and 2 females) volunteered for this study. [Methods] The subjects walked for 20 min on a treadmill while using a smartphone. To determine the effect of smartphone use, lumbar repositioning error was measured using an electronic goniometer while lumbar curvature was assessed using a Spinal Mouse before and immediately after treadmill use. Differences in the lumbar repositioning error and lumbar curvature data between the pre- and post-walking were compared using the paired t-test. [Results] The lumbar spine repositioning error was significantly greater post-walking compared with pre-walking (6.70±2.91° vs. 3.02±1.79°). There was no significant difference in lumbar curvature between pre- and post-walking (14.24±3.18° vs. 13.94±3.12°). [Conclusion] These findings indicate that the lumbar repositioning error increased immediately after walking while using a smartphone, but that the lumbar curvature was unchanged.

Immediate effects of an end-range mobilization technique on shoulder range of motion and skin temperature in individuals with posterior shoulder tightness.

[Purpose] This study investigated the effects of an end-range mobilization technique on the range of motion of the glenohumeral internal rotation and the skin temperature of the shoulder in individuals with posterior shoulder tightness. [Subjects] Thirteen subjects with posterior shoulder tightness who had glenohumeral internal rotation deficit ≥ 15° participated. [Methods] All subjects underwent glenohumeral joint end-range mobilization intervention. The internal rotation range of motion of the glenohumeral joint was measured by a goniometer and the shoulder skin temperature was measured by a digital infrared thermographic imaging device before and immediately after the intervention. Paired t-tests were used to analyze the differences in these parameter pre and post-intervention. [Results] The glenohumeral internal rotation range of motion and skin temperature of the posterolateral shoulder in increased significantly post-intervention. [Conclusion] The end-range mobilization technique is effective for increasing the glenohumeral internal rotation range of motion and skin temperature of the shoulder in individuals with posterior shoulder tightness.