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John H. Hollman

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John H. Hollman and Mayo Clinic

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James W. Youdas, Erica F. Loder, Jody L. Moldenhauer, Christine R. Paulsen and John H. Hollman

Context:

Hip-abductor weakness is associated with many lower extremity injuries. A simple procedure to assess hip-abductor performance is necessary in patient populations.

Objective:

To describe the change in pelvic-on-femoral position of the stance limb before and after 45 seconds of resisted sidestepping.

Design:

Cross-sectional comparative.

Setting:

Laboratory.

Participants:

24 healthy women (24.6 ± 3.5 years) and 14 healthy men (24.5 ± 3.0 years).

Main Outcome Measures:

Pelvic-on-femoral position in degrees in single-leg stance before and after 45 seconds of resisted sidestepping.

Results:

The difference between the baseline and postexercise measurements for both men and women was significant (P < .05). The effect of the resisted-sidestepping exercise on the hip abductors was not statistically different between men and women.

Conclusions:

Forty-five seconds of resisted sidestepping using an elastic band produced a change in pelvic-on-femoral position in healthy adults. This test might be useful to detect impaired performance in hip abductors of patients with injury elsewhere in the musculoskeletal system.

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James W. Youdas, Sara T. Mraz, Barbara J. Norstad, Jennifer J. Schinke and John H. Hollman

Context:

Hip abductor muscle weakness is related to many lower extremity injuries. A simple procedure, the Trendelenburg test, may be used to assess hip abductor performance in patient populations.

Objective:

To describe the minimal detectable change (MDC) in pelvic-on-femoral (P-O-F) position of the stance limb during the Trendelenburg test.

Setting:

Laboratory.

Participants:

45 healthy women (28 ± 8 years) and 45 healthy men (33 ± 11 years).

Main Outcome Measures:

P-O-F position in degrees in single-leg stance. Results: Baseline P-O-F position (hip adduction) was 83° ± 3° with a range from 76° to 94°. The intratester reliability (ICC3,1 for measurement of P-O-F position using a universal goniometer was 0.58 with a standard error of measurement (SEM) of 2°. The minimal detectable change (MDC) was calculated to be 4°.

Conclusions:

If a person’s P-O-F position changes less than 4° between measurements, then the P-O-F position is within measurement error and it can be determined that there has been no change in the performance of the hip abductor muscles when examined by the Trendelenburg test.

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John H. Hollman, Kimberly E. Kolbeck, Jamie L. Hitchcock, Jonathan W. Koverman and David A. Krause

Context:

Hip-muscle weakness might be associated with impaired biomechanics and postures that contribute to lower extremity injuries.

Objective:

To examine relationships between hip-muscle strength, Q angle, and foot pronation.

Design:

Correlational study.

Setting:

Academic laboratory.

Participants:

33 healthy adults.

Main Outcome Measures:

Maximal isometric hip abduction (Abd), adduction (Add), external-rotation (ER) and internal-rotation (IR) strength; Q angle of the knee; and longitudinal arch angle of the foot. We analyzed Pearson product– moment (r) correlation coefficients between the Abd/Add and ER/IR force ratios, Q angle, and longitudinal arch angle.

Results:

The hip Abd/Add force ratio was correlated with longitudinal arch angle (r = .35, P = .025).

Conclusions:

Reduced strength of the hip abductors relative to adductors is associated with increased pronation at the foot. Clinicians should be aware of this relationship when examining patients with lower extremity impairments.

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James W. Youdas, Timothy J. McLean, David A. Krause and John H. Hollman

Context:

Posterior calf stretching is believed to improve active ankle dorsiflexion range of motion (AADFROM) after acute ankle-inversion sprain.

Objective:

To describe AADFROM at baseline (postinjury) and at 2-wk time periods for 6 wk after acute inversion sprain.

Design:

Randomized trial.

Setting:

Sports clinic.

Participants:

11 men and 11 women (age range 11–54 y) with acute inversion sprain.

Intervention:

Standardized home exercise program for acute inversion sprain.

Main Outcome Measure:

AADFROM with the knee extended.

Results:

Time main effect on AADFROM was significant (F 3,57 = 108, P < .001). At baseline, mean active sagittal-plane motion of the ankle was 6° of plantar flexion, whereas at 2, 4, and 6 wk AADFROM was 7°, 11°, and 11°, respectively.

Conclusions:

AADFROM increased significantly from baseline to week 2 and from week 2 to week 4. Normal AADFROM was restored within 4 wk after acute inversion sprain.

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John H. Hollman, Jeffrey M. Hohl, Jordan L. Kraft, Jeffrey D. Strauss and Katie J. Traver

Context:

Abnormal lower extremity kinematics during dynamic activities may be influenced by impaired gluteus maximus function.

Objective:

To examine whether hip-extensor strength and gluteus maximus recruitment are associated with dynamic frontal-plane knee motion during a jump-landing task.

Design:

Exploratory study.

Setting:

Biomechanics laboratory.

Participants:

40 healthy female volunteers.

Main Outcome Measures:

Isometric hip-extension strength was measured bilaterally with a handheld dynamometer. Three-dimensional hip and knee kinematics and gluteus maximus electromyography data were collected bilaterally during a jumplanding test. Data were analyzed with hierarchical linear regression and partial correlation coefficients (α = .05).

Results:

Hip motion in the transverse plane was highly correlated with knee motion in the frontal plane (partial r = .724). After controlling for hip motion, reduced magnitudes of isometric hip-extensor strength (partial r = .470) and peak gluteus maximus recruitment (partial r = .277) were correlated with increased magnitudes of knee valgus during the jump-landing task.

Conclusion:

Hip-extensor strength and gluteus maximus recruitment, which represents a measure of the muscle’s neuromuscular control, are both associated with frontal-plane knee motions during a dynamic weight-bearing task.

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David A. Krause, Beth A. Cloud, Lindsey A. Forster, Jennifer A. Schrank and John H. Hollman

Context:

Limited ankle DF (DF) range of motion (ROM) resulting from restricted gastrocnemius and soleus mobility is associated with a variety of lower extremity pathologies. Several techniques are used clinically to measure ankle DF.

Objectives:

To evaluate the reliability and minimal detectable change of DF ROM measurement, determine whether there is a difference in measured DF between techniques, and quantify the electromyographic (EMG) activity of the soleus and tibialis anterior muscles associated with the techniques.

Design:

Repeated measures.

Setting:

Controlled laboratory setting.

Participants:

39 healthy subjects, age 22–33.

Main Outcome Measures:

DF measurements using 5 different techniques including active and passive DF with the knee extended and flexed to 90° and a modified lunge. EMG activity of the soleus and anterior tibialis muscles.

Results:

Intrarater reliability values (ICC3,1) ranged from .68 to .89. Interrater reliability (ICC2,1) ranged from .55 to .82. ICCs were the greatest with the modified lunge. The minimal detectable change (MDC95) ranged from 6° to 8° among the different techniques. A significant difference in DF ROM was found between all methods. Measurements taken with active DF were greater than the same measures taken passively. The lunge position resulted in greater DF ROM than both active and passive techniques. EMG activity of the soleus was greater with active DF and the lunge than with passive DF.

Conclusions:

The modified lunge, which demonstrated excellent intrarater and interrater reliability, may best represent maximal DF. Active end-range DF was significantly greater than passive end-range DF when measured at either 0° or 90° knee flexion. Greater active DF was not explained by inhibition of the soleus. Finally, using the modified lunge, a difference between 2 measurements over time of 6° or more suggests that a meaningful change has occurred.

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James W. Youdas, Kady E. Adams, John E. Bertucci, Koel J. Brooks, Meghan M. Nelson and John H. Hollman

Context:

No published studies have compared muscle activation levels simultaneously for the gluteus maximus and medius muscles of stance and moving limbs during standing hip-joint strengthening while using elastic-tubing resistance.

Objective:

To quantify activation levels bilaterally of the gluteus maximus and medius during resisted lower-extremity standing exercises using elastic tubing for the cross-over, reverse cross-over, front-pull, and back-pull exercise conditions.

Design:

Repeated measures.

Setting:

Laboratory.

Participants:

26 active and healthy people, 13 men (25 ± 3 y) and 13 women (24 ± 1 y).

Intervention:

Subjects completed 3 consecutive repetitions of lower-extremity exercises in random order.

Main Outcome Measures:

Surface electromyographic (EMG) signals were normalized to peak activity in the maximum voluntary isometric contraction (MVIC) trial and expressed as a percentage. Magnitudes of EMG recruitment were analyzed with a 2 × 4 repeated-measures ANOVA for each muscle (α = .05).

Results:

For the gluteus maximus an interaction between exercise and limb factor was significant (F 3,75 = 21.5; P < .001). The moving-limb gluteus maximus was activated more than the stance limb's during the back-pull exercise (P < .001), and moving-limb gluteus maximus muscle recruitment was greater for the back-pull exercise than for the cross-over, reverse cross-over, and front-pull exercises (P < .001). For the gluteus medius an interaction between exercise and limb factor was significant (F 3,75 = 3.7; P < .03). Gluteus medius muscle recruitment (% MVIC) was greater in the stance limb than moving limb when performing the front-pull exercise (P < .001). Moving-limb gluteus medius muscle recruitment was greater for the reverse cross-over exercise than for the cross-over, front-pull, and back-pull exercises (P < .001).

Conclusions:

From a clinical standpoint there is no therapeutic benefit to selectively activate the gluteus maximus and gluteus medius muscles on the stance limb by resisting sagittal- and frontal-plane hip movements on the moving limb using resistance supplied by elastic tubing.

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John H. Hollman, Tyler A. Berling, Ellen O. Crum, Kelsie M. Miller, Brent T. Simmons and James W. Youdas

Context: Hip extension with hamstring-dominant rather than gluteus maximus-dominant recruitment may increase anterior femoracetabular forces and contribute to conditions that cause hip pain. Cueing methods during hip extension exercises may facilitate greater gluteus maximus recruitment. Objective: We examined whether specific verbal and tactile cues facilitate gluteus maximus recruitment while inhibiting hamstring recruitment during a bridging exercise. Design: Randomized controlled trial. Setting: Biomechanics laboratory. Participants: 30 young adult women (age 24 [3] y; BMI 22.2 [2.4] kg/m2). Intervention: Participants were tested over 2 sessions, 1 week apart, while performing 5 repetitions of a bridging exercise. At their second visit, participants in the experimental group received verbal and tactile cues intended to facilitate gluteus maximus recruitment and inhibit hamstring recruitment. Control group participants received no additional cues beyond original instructions. Main Outcome Measures: Gluteus maximus and hamstring recruitment were measured with surface electromyography, normalized to maximal voluntary isometric contractions (MVICs). Results: Gluteus maximus recruitment was unchanged in the control group and increased from 16.8 to 33.0% MVIC in the cueing group (F = 33.369, P < .001). Hamstring recruitment was unchanged in the control group but also increased from 16.5 to 29.8% MVIC in the cueing group (F = 6.400, P = .02). The effect size of the change in gluteus maximus recruitment in the cueing group (Cohen’s d = 1.5, 95% CI = 0.9 to 2.2) was not significantly greater than the effect size in hamstring recruitment (Cohen’s d = 0.8, 95% CI = 0.1 to 1.5). Conclusions: Verbal and tactile cues hypothesized to facilitate gluteus maximus recruitment yielded comparable increases in both gluteus maximus and hamstring recruitment. If one intends to promote hip extension by facilitating gluteus maximus recruitment while inhibiting hamstring recruitment during bridging exercises, the cueing methods employed in this study may not produce desired effects.