Differential activation of psoas major and rectus femoris during active straight leg raise to end range

The purpose of this study was to investigate the activation of the hip flexor and abdominal muscles during an active straight leg raise (ASLR) to end range of hip flexion. Data were recorded from nine healthy men. Fine-wire electromyography (EMG) electrodes were inserted into psoas major (PM), and surface electrodes were placed over rectus femoris (RF), rectus abdominis, obliquus externus abdominis (OE), and obliquus internus abdominis/transversus abdominis (OI/TrA). EMG and kinematic data were obtained during concentric, hold (at end range) and eccentric phases of an ASLR. Concentric and eccentric movements were divided into three phases (early, mid, and late). Onsets of EMG relative to the onset of the ALSR movement and EMG amplitudes in each phase were compared between muscles. Onsets of the PM (-33 ± 245 ms) and RF (-3 ± 119 ms) EMG prior to leg elevation were significantly earlier than those of the OE and OI/TrA. PM EMG showed highest activation in the late concentric, hold, early eccentric phase, and was significantly higher than RF EMG. OI/TrA EMG was significantly greater in mid and late concentric, hold, and early eccentric phase than other phases. During the ASLR, unlike RF, PM EMG continues to increase towards the end range of hip flexion. Activation of OI/TrA muscle may be involved in control trunk and pelvic movement.

A multivariate model for predicting PPGP considering postural adjustment parameters

BACKGROUND

Prospective studies have described evidence about the risk of developing pregnancy-related pelvic girdle pain (PPGP) such as, parity, previous history of low back and pelvic girdle pain. No previous studies have prospectively associated PPGP with postural control.

AIM

This study aimed to identify postural control predictors of PPGP during pregnancy.

METHODS

Forty-six pregnant women were surveyed throughout their pregnancy for the presence of PPGP. At baseline, participants were evaluated for muscle latencies, mediolateral centre-of-pressure (COP) displacement and velocity during single-leg lift performed with eyes open and closed. PPGP was considered if they presented with one positive clinical assessment as well as pain within the pelvic area.

RESULTS

Eighteen (45%) of the participants developed PPGP. This group presented with PPGP around a mean 29th week (SD = 5.7), with mean pelvic pain intensity of 4 mm VAS (SD = 2) on a (0-10 cm VAS) and mean PPGP questionnaire score of 21.5 points (SD = 10.6) out of a possible 100 points with 0 indicating no functional disability. The two factors that were significantly associated with PPGP were the right and left biceps femoris (BF) muscle. For every 50 ms of difference of BF muscles latency between eyes open and closed, the risk of PPGP increases by 20% (right BF) and 30% (left BF) to develop PPGP.

CONCLUSION(S)

This study shows that BF muscle delay during single-leg lift presented at baseline was a significant predictor for the development of PPGP in late pregnancy.

Characterizing gait abnormalities in patients with cervical spondylotic myelopathy: a neuromuscular analysis

BACKGROUND CONTEXT

Gait impairment is a hallmark of cervical spondylotic myelopathy (CSM). It has been shown to affect quality of life but has not been well defined. Further electromyographic (EMG) characterization of the gait cycle may help elucidate the true neuromuscular pathology with implications on prognosis and rehabilitation techniques.

PURPOSE

This study compares neuromuscular activity in patients with CSM to that of healthy age-matched controls.

STUDY DESIGN

Nonrandomized, prospective, concurrent control cohort study.

METHODS

Neuromuscular activity was measured in 40 patients with symptomatic CSM during a series of over-ground gait trials at a self-selected speed before surgical intervention. External oblique, multifidus, erector spinae, rectus femoris, semitendinosus, tibialis anterior, medial gastrocnemius, and medial deltoid were assessed. Identical measurements were taken in 25 healthy control patients. Differences in time of muscle onset, peak EMG, time to peak EMG, and integrated electromyography (iEMG) were assessed using one-way ANOVA.

RESULTS

There were no significant differences between patients with CSM and healthy controls with respect to time of muscle contraction onset. Peak EMG muscle activity was significantly higher in the medial deltoid of patients with CSM (39.3% vs. 23.3% sMVC, p=.042), but no other differences were seen in the remaining muscles tested. They also demonstrated significantly longer time to peak EMG muscle activity compared with controls in 5 of the 8 muscles tested, including the multifidus (20.2 vs. 16.8 ms, p=.050), erector spinae (18.2 vs. 8.9 ms, p<.001), semitendinosis (26.3 vs. 22.4 ms, p=.037), tibialis anterior (14.7 vs. 11.0 ms, p=.050), and medial deltoid (24.2 vs. 9.2 ms, p<.001). Compared with controls, patients with CSM demonstrated significantly higher iEMG activity in the semitendinosis (586.5% vs. 272.5 sMVC, p=.047) and medial deltoid (87.62% vs. 22.5% sMVC, p=.008).

CONCLUSIONS

The onset of muscle activity is not delayed in CSM patients, but many key muscles take longer to fully contract. This produces a situation in which patients with CSM are unable to fully fire their muscles with sufficient speed to maintain a normal gait. The core and lower extremity muscles do not contract with increased peak amplitude in response, but the deltoid and hamstring muscles are more active, suggesting compensatory activity as patients attempt to maintain balance. The end result is less efficient ambulation. These findings provide a more nuanced understanding of gait in individuals suffering from CSM and may have implications on rehabilitation protocols.

A Comparison of Muscular Activity During Gait Between Walking Sticks and a Walker in Patients With Adult Degenerative Scoliosis

STUDY DESIGN

A repeated measurement, single-center, prospective study.

OBJECTIVE

The purpose of this study is to compare and contrast the benefits of walking sticks versus a walker on the trunk and lower extremity muscular control in patients with adult degenerative scoliosis (ADS).

SUMMARY OF BACKGROUND DATA

ADS patients demonstrate an altered gait pattern. Walking aids help maintain mobility in those patients. Whereas a walker forces patients into kyphosis, the higher grips of walking sticks allows for more upright posture, arm swing, and improved sagittal alignment.

METHODS

Twenty ADS patients with symptomatic degenerative scoliosis performed over-ground walking at self-selected speed under 3 testing conditions: 1) with walking sticks (WS); 2) with walker (WR); and 3) without any device (ND). Trunk and lower extremity peak muscle activation, time to peak muscle activity, muscle duration, muscle onset, and integrated electromyography (iEMG) were measured and compared.

RESULTS

The use of WS produced increases in muscle activity in the external oblique (WS: 44.3% vs. WR: 7.4% of submaximum voluntary contraction [sMVC], p = .007) and medial gastrocnemius (WS: 78.8% vs ND: 43.7% of sMVC, p = .027) in comparison to the walker and no device, respectively. When using WS, shorter muscle activity time was observed for rectus femoris (WS: 62.9% vs. WR: 88.8% of gait cycle, p = .001), semitendinosus (WS: 64.3% vs. WR: 93.0% of gait cycle, p = .003), tibialis anterius (WS: 59.4% vs. WR: 85.1% of gait cycle, p = .001), and medial gastrocnemius (WS: 67.3% vs. WR: 98.0% of gait cycle, p = .006) in comparison to the walker.

CONCLUSIONS

The use of walking sticks can potentially promote trunk and lower extremity neuromuscular control and gait mechanics comparable to gait without any assistive devices. Although the differences in magnitudes between comparisons were small and should be cautiously interpreted on a case-by-case basis, based on this study's results and our anecdotal experience treating patients with ADS, we recommend the use of walking sticks to assist with their gait prior to and after surgical intervention.

LEVEL OF EVIDENCE

Level III.