RESUMEN
STUDY DESIGN: Controlled laboratory study. BACKGROUND: The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment. Motion-mode (M-mode) ultrasound enables noninvasive measurements of the onset of deep and superficial muscle motion, which is associated with activation onset. OBJECTIVES: To compare (1) the onset of superficial and deep gluteus medius and gluteus minimus muscle motion relative to the instant of peak ground reaction force and (2) the level of swing-phase muscle motion during step-down between subjects with chronic hip pain and controls using M-mode ultrasound. METHODS: Thirty-five subjects with anterior, nontraumatic hip pain for more than 6 months (mean ± SD age, 54 ± 9 years) and 35 controls (age, 57 ± 7 years) were scanned on the lateral hip of the leading leg during frontal step-down onto a force platform using M-mode ultrasound. Computerized motion detection with the Teager-Kaiser energy operator was applied on the gluteus minimus and the deep and superficial gluteus medius to determine the time lag between muscle motion onset and instant of peak ground reaction force and the level of gluteus minimus motion during the swing phase. Time lags and motion levels were averaged per subject, and t tests were used to determine between-group differences. RESULTS: In participants with hip pain, gluteus minimus motion onset was 103 milliseconds earlier (P = .002) and superficial gluteus medius motion was 70 milliseconds earlier (P = .047) than those in healthy control participants. The level of gluteus minimus swing-phase motion was higher with pain (P = .006). CONCLUSION: Increased gluteus minimus motion during the swing phase and earlier gluteus minimus and superficial gluteus medius motion in individuals with hip pain suggest an overall increase of muscle activity, possibly a protective behavior.
Asunto(s)
Artralgia/fisiopatología , Dolor Crónico/fisiopatología , Cadera/fisiopatología , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/fisiología , Adulto , Nalgas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Movimiento , Tiempo de Reacción , UltrasonografíaRESUMEN
M-mode ultrasound imaging (US) reflects motion of connective tissue within muscles. As muscle contraction is accompanied by motion of muscle tissue, M-mode US may be used to measure non-invasively the onset of deep muscle activity. Isometric hip abduction was measured on nine healthy subjects in the deep region of the gluteus medius muscle and in gluteus minimus by fine-wire electromyography (EMG) and M-mode US. Following signal transformation with the Teager-Kaiser Energy Operator, EMG and M-mode US onsets of muscle activity were computer-processed. Correlation between log-transformed EMG and M-mode high-energy onsets was higher in gluteus medius (r 0.93) than in gluteus minimus (r 0.86). M-mode high-energy onsets followed EMG onset by median 33 (IQR 53) ms in gluteus medius, and by 17 (IQR 63) ms in gluteus minimus. 4% of gluteus medius and 23% of gluteus minimus M-mode onsets were detected before EMG onset. Using a higher onset threshold reduced the rate of onsets detected before EMG but also prediction accuracy. In voluntary activation, M-mode US high-energy onsets were closely related to EMG-measured onsets, but the time interval between both measures varied. The relationship of electrical and mechanical activation onsets appears to be influenced by modifying factors which may differ between muscles.
Asunto(s)
Contracción Isométrica/fisiología , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/fisiología , Ultrasonografía Doppler/métodos , Adulto , Electromiografía/métodos , Femenino , Cadera/diagnóstico por imagen , Cadera/fisiología , Humanos , Masculino , Contracción Muscular/fisiologíaRESUMEN
The clinical assessment of gluteus medius and minimus force sharing requires non-invasive measurements of individual activity levels. Do ultrasound measurements of change of muscle thickness substitute invasive electromyography (EMG)? Isometric hip abduction in 20-80% maximal voluntary isometric contraction (MVIC) was measured using dynamometry, M-mode ultrasound for gluteus medius and minimus thickness and EMG using (1) surface electrodes on gluteus medius, n = 15, (2) fine-wire electrodes in deep gluteus medius and minimus, n = 6. Gluteus medius thickened by 5.0 (SD 2.5) mm at 80% MVIC while gluteus minimus thickness was constant in the surface EMG study and decreased by 1.6 (SD 1.6) mm at the more ventral location in the fine-wire EMG study. Thickness change of gluteus medius enabled prediction of torque (r(2) 0.66) and of surface EMG amplitude (r(2) 0.57). Surface EMG enabled higher torque prediction (r(2) 0.84) than thickness change. Thickness change of gluteus minimus did not enable a practically relevant estimation of torque production. Ultrasound examination revealed a differential thickening behaviour of gluteus medius and minimus which enabled estimation of isometric torque production only for gluteus medius but with lower precision than surface EMG.
Asunto(s)
Nalgas , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/fisiología , Adulto , Electromiografía , Femenino , Humanos , Masculino , Contracción Muscular/fisiología , Torque , UltrasonografíaRESUMEN
The hip abductors gluteus medius (Gmed) and minimus (Gmin) differ slightly in function and how they are affected by hip joint pathology. A separate assessment of Gmed and Gmin is feasible by ultrasound (US) imaging. B-mode and M-mode US can be used to measure muscle thickness. Two B- and two M-mode scans of Gmed and Gmin thickness were taken in relaxation on 16 asymptomatic volunteers, repeated within 4 days on 11 subjects. Three types of intra-rater reliability of muscle thickness measurements were examined: (1) within-session reliability comparing two scans from the same session, (2) between-days reliability comparing thickness from two scanning occasion within 4 days and (3) reliability of taking thickness measurements by re-measuring the same US scans after 1 week. Thickness measurements on B- and M-mode images provided ICC3,1 >0.96 for within-session reliability. ICC3,k >0.89 for between-days reliability and ICC3,1 >0.85 for re-reading the same scans were estimated. Minimal detectable changes >1.0 mm within-session, >2.4 mm between-days and >1.7 mm for re-reading scans indicated that small thickness changes are not detectable. The investigation suggests a slight advantage for fascia recognition in B-mode and the advantage of visual control of muscle relaxation in M-mode.
Asunto(s)
Electromiografía/métodos , Articulación de la Cadera/fisiología , Músculo Esquelético/diagnóstico por imagen , Ultrasonografía Doppler/métodos , Adulto , Nalgas , Femenino , Voluntarios Sanos , Humanos , Masculino , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Variaciones Dependientes del Observador , Rango del Movimiento Articular/fisiología , Valores de Referencia , Muestreo , Adulto JovenRESUMEN
BACKGROUND: Joint position sense (JPS) in the knee has been shown by many authors to decline with age. It has been speculated that this decrease contributes to abnormal joint mechanics during load-bearing activities and putatively results in joint degeneration. Surprisingly little research has been conducted on the human hip to determine benchmarks for normal JPS. METHOD: Fifty-nine community dwelling subjects, 30 young (mean age 21.7 years) and 29 older (mean age 75 years), were recruited to determine normal reference ranges for the effect of age on hip JPS. Active and passive repositioning tasks were performed in inner and outer ranges of the hip abduction plane of movement. An electromagnetic tracking system was used to obtain accurate error measurements of the angular displacement. RESULTS: Results indicated no difference in hip JPS between the young and older subjects (F(1,57) = 0.011, p = .917). However, it was found that for both age groups, accurate reproduction of position at the hip joint occurred in the inner range (F(1,57) = 13.760, p < .001). For both groups, active repositioning was more accurate than passive (F(1,57) = 9.265, p = .004). CONCLUSIONS: In this study, no difference in hip JPS was found between young and older subjects. Accuracy was greater in the inner range, with active repositioning demonstrating higher precision compared to passive repositioning of the limb.