The importance of sensory-motor control in providing core stability: implications for measurement and training

Effects of fatigue on trunk stability in elite gymnasts

The aim of the present study was to test the hypothesis that fatigue due to exercises performed in training leads to a decrement of trunk stability in elite, female gymnasts. Nine female gymnasts participated in the study. To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed. Before and after the fatigue protocol, participants performed three trials of a balancing task while sitting on a seat fixed over a hemisphere to create an unstable surface. A force plate tracked the location of the center of pressure (CoP). In addition, nine trials were performed in which the seat was backward inclined over a set angle and suddenly released after which the subject had to regain balance. Sway amplitude and frequency in unperturbed sitting were determined from the CoP time series and averaged over trials. The maximum displacement and rate of recovery of the CoP location after the sudden release were determined and averaged over trials. After the fatigue protocol, sway amplitude in the fore-aft direction was significantly increased (p = 0.03), while sway frequency was decreased (p = 0.005). In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05). Fatigue induced by series of exercises representing a realistic training load caused a measurable decrement in dynamic stability of the trunk in elite gymnasts.

Effect of spinal manipulation on sensorimotor functions in back pain patients: study protocol for a randomised controlled trial

Background

Low back pain (LBP) is a recognized public health problem, impacting up to 80% of US adults at some point in their lives. Patients with LBP are utilizing integrative health care such as spinal manipulation (SM). SM is the therapeutic application of a load to specific body tissues or structures and can be divided into two broad categories: SM with a high-velocity low-amplitude load, or an impulse "thrust", (HVLA-SM) and SM with a low-velocity variable-amplitude load (LVVA-SM). There is evidence that sensorimotor function in people with LBP is altered. This study evaluates the sensorimotor function in the lumbopelvic region, as measured by postural sway, response to sudden load and repositioning accuracy, following SM to the lumbar and pelvic region when compared to a sham treatment.

Methods/Design

A total of 219 participants with acute, subacute or chronic low back pain are being recruited from the Quad Cities area located in Iowa and Illinois. They are allocated through a minimization algorithm in a 1:1:1 ratio to receive either 13 HVLA-SM treatments over 6 weeks, 13 LVVA-SM treatments over 6 weeks or 2 weeks of a sham treatment followed by 4 weeks of full spine "doctor's choice" SM. Sensorimotor function tests are performed before and immediately after treatment at baseline, week 2 and week 6. Self-report outcome assessments are also collected. The primary aims of this study are to 1) determine immediate pre to post changes in sensorimotor function as measured by postural sway following delivery of a single HVLA-SM or LVVA-SM treatment when compared to a sham treatment and 2) to determine changes from baseline to 2 weeks (4 treatments) of HVLA-SM or LVVA-SM compared to a sham treatment. Secondary aims include changes in response to sudden loads and lumbar repositioning accuracy at these endpoints, estimating sensorimotor function in the SM groups after 6 weeks of treatment, and exploring if changes in sensorimotor function are associated with changes in self-report outcome assessments.

Discussion

This study may provide clues to the sensorimotor mechanisms that explain observed functional deficits associated with LBP, as well as the mechanism of action of SM.

Trial registration

This trial is registered in ClinicalTrials.gov, with the ID number of NCT00830596, registered on January 27, 2009. The first participant was allocated on 30 January 2009 and the final participant was allocated on 17 March 2011.

Interday reliability of peak muscular power outputs on an isotonic dynamometer and assessment of active trunk control using the chop and lift tests

CONTEXT

Assessment techniques used to measure functional tasks involving active trunk control are restricted to linear movements that lack the explosive movements and dynamic tasks associated with activities of daily living and sport. Reliable clinical methods used to assess the diagonal and ballistic movements about the trunk are lacking.

OBJECTIVE

To assess the interday reliability of peak muscular power outputs while participants performed diagonal chop and lift tests and maintained a stable trunk.

DESIGN

Controlled laboratory study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Eighteen healthy individuals (10 men and 8 women; age  =  32 ± 11 years, height  =  168 ± 12 cm, mass  =  80 ± 19 kg) from the general population participated.

INTERVENTION(S)

Participants performed 2 power tests (chop, lift) using an isotonic dynamometer and 3 endurance tests (Biering-Sørensen, side-plank left, side-plank right) to assess active trunk control. Testing was performed on 3 different days separated by at least 1 week. Reliability was compared between days 1 and 2 and between days 2 and 3. Correlations between the power and endurance tests were evaluated to determine the degree of similarity.

MAIN OUTCOME MEASURE(S)

Peak muscular power outputs (watts) derived from a 1-repetition maximum protocol for the chop and lift tests were collected for both the right and left sides.

RESULTS

Intraclass correlation coefficients for peak muscular power were highly reliable for the chop (range, 0.87-0.98), lift (range, 0.83-0.96), and endurance (range, 0.80-0.98) tests between test sessions. The correlations between the power assessments and the Biering-Sørensen test (r range, -0.008 to 0.017) were low. The side-plank tests were moderately correlated with the chop (r range, 0.528-0.590) and the lift (r range, 0.359-0.467) tests.

CONCLUSIONS

The diagonal chop and lift power protocol generated reliable data and appears to be a dynamic test that simulates functional tasks, which require dynamic trunk control.

Femoroacetabular impingement: a common cause of hip pain in young adults

OBJECTIVE

Femoroacetabular impingement (FAI) is a common cause of hip discomfort in young adults. Recently, a better understanding of the pathomechanics and morphologic abnormalities in the hip has implicated FAI as a possible factor in early osteoarthrosis. The clinical presentation, physical examination findings, and radiographic features are discussed in this article.

DATA SOURCES

PubMed was searched using words and terms including femoacetabular impingement, hip osteoarthritis, hip arthroscopy, early osteoarthrosis, and hip dislocation. References of relevant studies were searched by hand.

STUDY SELECTION

All studies directly involving the treatment of FAI were reviewed by 3 authors and selected for further analysis, including expert opinion and review articles.

DATA SYNTHESIS

The quality of each study was assessed, and the results were summarized.

CONCLUSIONS

Conservative measures, including physical therapy, restriction of activities, core strengthening, improvement of sensory-motor, and control and nonsteroidal anti-inflammatories are the mainstays of nonsurgical treatment. However, surgical management is often necessary to allow full return to activity with options including surgical dislocation of the hip, hip arthroscopy, periacetabular and rotational osteotomies, and combined hip arthroscopy with a limited open exposure. Although the literature is replete with short-term evidence to support surgical treatment, there are currently no long-term prospective data or natural history studies examining the implications of FAI and effects of early intervention.

Lower extremity neuromuscular control immediately after fatiguing hip-abduction exercise

CONTEXT

Fatigue of the gluteus medius (GMed) muscle might be associated with decreases in postural control due to insufficient pelvic stabilization. Men and women might have different muscular recruitment patterns in response to GMed fatigue.

OBJECTIVE

To compare postural control and quality of movement between men and women after a fatiguing hip-abduction exercise.

DESIGN

Descriptive laboratory study.

SETTING

Controlled laboratory.

PATIENTS OR OTHER PARTICIPANTS

Eighteen men (age = 22 ± 3.64 years, height = 183.37 ± 8.30 cm, mass = 87.02 ± 12.53 kg) and 18 women (age = 22 ± 3.14, height = 167.65 ± 5.80 cm, mass = 66.64 ± 10.49 kg) with no history of low back or lower extremity injury participated in our study.

INTERVENTION(S)

Participants followed a fatiguing protocol that involved a side-lying hip-abduction exercise performed until a 15% shift in electromyographic median frequency of the GMed was reached.

MAIN OUTCOME MEASURE(S)

Baseline and postfatigue measurements of single-leg static balance, dynamic balance, and quality of movement assessed with center-of-pressure measurements, the Star Excursion Balance Test, and lateral step-down test, respectively, were recorded for the dominant lower extremity (as identified by the participant).

RESULTS

We observed no differences in balance deficits between sexes (P > .05); however, we found main effects for time with all of our postfatigue outcome measures (P ≤ .05).

CONCLUSIONS

Our findings suggest that postural control and quality of movement were affected negatively after a GMed-fatiguing exercise. At similar levels of local muscle fatigue, men and women had similar measurements of postural control.

The effect of core stability training on balance and mobility in ambulant individuals with multiple sclerosis: a multi-centre series of single case studies

BACKGROUND

Core stability training is popular in the management of people with multiple sclerosis (MS); however, scientific evidence to support its effectiveness is scarce.

OBJECTIVE

To explore the effectiveness of core stability training on balance and mobility.

METHOD

A multi-centre series of eight single case studies was undertaken. Eight ambulant individuals with stable MS participated in 16 face-to-face core stability training sessions, delivered by a neurophysiotherapist, plus a daily home exercise programme. A range of outcomes were measured: 10-m timed walk, 12-item MS walking scale, timed get up and go, functional reach tests, timed single leg stance, visual analogue scales of two activities, and the Activities-specific Balance Confidence Scale.

RESULTS

Visual analysis of trend, level and slope demonstrated improvement in five subjects (62%) in seven measures. This was confirmed by the two standard deviation band method of analysis for six measures. Analysis of group data (repeated measures within subjects analysis of variance) indicated significant improvement between baseline and intervention phases for timed walk (p = 0.019), MSWS-12 Scale (p = 0.041), forward (p = 0.015) and lateral reach (p = 0.012). In general, no further improvements were made following withdrawal of the intervention.

CONCLUSIONS

This study provides preliminary evidence of the effectiveness of an 8-week core stability training programme in improving balance and mobility in ambulant people with MS. Variations in response to intervention are evident. Assessor-blinded randomized controlled studies are required to confirm these findings and determine patient characteristics which identify those who benefit most from this intervention.

Quantifying core stability: a technical report

In prior research, we used 4 stability platform tests as a measurement of core stability and found that scores on the third and fourth days of testing were essentially the same for each of the 4 tests. Lafayette Instrument Co. subsequently made us a prototype stability platform to enhance this research. The purpose of the present research was to determine the effect of changes in (1) equipment and (2) number of test administrations on test reliability. We also increased the number of test administrations on each day from 5 to 10 but only used the quadruped arm raise test. The subjects were 25 university students; each was tested on 10 trials of 30-seconds duration on 4 different days to enable us to study the learning effect. All 10 trials for the first day, as well as the first trial on the 3 subsequent days of testing, were used as practice trials. Trials 2 to 6 on testing days 2 to 4 were chosen for the data analysis. With 5 trials, the maximum score attainable was 150 seconds.; the means were 125 for day 2 and 132 for both days 3 and 4. Internal consistency intraclass reliability coefficients based on a 1-way analysis of variance model and a criterion score, which was the sum or mean of trials 2 to 6 for days 2 to 4, were 0.89, 0.95, and 0.92, respectively. Stability reliabilities were 0.76 and 0.92 for day 2 versus day 3 and day 3 versus day 4, respectively. Although we had hoped to show that only 2 days of testing would be required in future research, because of learning effect, 3 will be needed.

Core stability: inter- and intraobserver reliability of 6 clinical tests

OBJECTIVE

Core stability is a complex concept within sports medicine and is thought to play a role in sports injuries. There is a lack of reliable and valid clinical tests for core stability. The inter- and intraobserver reliability of 6 tests commonly used to assess core stability was determined.

DESIGN

A video of the tests was shown to 6 observers. A second observation took place 5 weeks later with the same observers.

SETTING

Sports medicine department of a hospital.

PARTICIPANTS

Forty male athletes. ASSESSMENT OF VARIABLES: Core stability was rated as poor, moderate, good, or excellent by each observer for each of the 6 tests.

MAIN OUTCOME MEASURES

Inter- and intraobserver reliability.

RESULTS

The mean score of all tests was 13.4% poor, 33.3% moderate, 40.1% good, and 13.2% excellent. The intraclass correlation coefficients (ICCs 2,1) for the interobserver reliability for frontal, sagittal, and transverse plane evaluation were 0.09, 0.32, and 0.51, respectively. The ICCs for the unilateral squat, the lateral step-down, and the bridge were 0.41, 0.39, and 0.36, respectively. The ICCs for the intraobserver reliability for frontal, sagittal, and transverse plane evaluation were 0.31, 0.40, and 0.55, respectively. The ICCs for the unilateral squat, the lateral step-down, and the bridge were 0.55, 0.49, and 0.21, respectively.

CONCLUSIONS

The 6 clinical core stability tests are not reliable when a 4-point visual scoring assessment is used. Future research on movement evaluation should be focused on more specific rating methods and training for the observers.

Effects of pitavastatin on adiponectin in patients with hyperlipidemia

The effects of treatment with pitavastatin on inflammatory and platelet activation markers and adiponectin in 117 patients with hyperlipidemia were investigated to determine whether pitavastatin may prevent the progression of atherosclerotic changes in hyperlipidemic patients. Adiponectin levels prior to pitavastatin treatment in hyperlipidemic patients with and without diabetes were lower than levels in normolipidemic controls. Both total cholesterol and the low-density lipoprotein cholesterol decreased significantly after pitavastatin administration. Additionally, hyperlipidemic patients with or without type 2 diabetes exhibited a significant increase in adiponectin levels 6 months after pitavastatin treatment (diabetes: 3.52 +/- 0.80 vs. 4.52 +/- 0.71 microg/ml, p < 0.001; no diabetes: 3.48 +/- 0.71 vs. 4.23 +/- 0.82 microg/ml, p < 0.05). However, high-sensitivity C-reactive protein, platelet-derived microparticle and soluble P-selectin did not exhibit any differences before or after pitavastatin administration. Levels of adiponectin significantly increased after pitavastatin administration in the group of lower soluble P-selectin (soluble P-selectin before pitavastatin treatment <200 ng/ml). These results suggest that pitavastatin possesses an adiponectin-increasing effect in patients with hyperlipidemia and this effect is influenced by intensive platelet activation.