Lower impulsive loadings following intensive weight loss after bariatric surgery in level and stair walking: a preliminary study.

BACKGROUND: There are currently very few of studies which have evaluated the role of bariatric surgery in joint loadings and changes in gait. We wanted to examine how impulsive loading would change level and stair walking in severely or morbidly obese subjects after they had undergone bariatric surgery and weight loss. METHODS: Thirteen female and three male adults aged between 30 and 63 years, cleared for Roux-en-Y gastric bypass, were recruited into this study. All subjects were severely or morbidly obese i.e., body mass index was >35 kg/m(2). The measurement methods consisted of triaxial skin mounted accelerometers and ground reaction force (GRF); conducted at two different predetermined gait speeds. RESULTS: The average weight loss was 27.4 (SD8.7) kg after 8.8 (SD3.9) months of follow-up period. Most of the absolute GRF parameters decreased in proportion to weight loss. However, medio-lateral GRF parameters decreased more than expected. The general trend in the knee accelerations demonstrated lower impulsive loadings in both axial and horizontal directions after weight loss. We did not observe any significant changes in stair walking. CONCLUSIONS: Weight loss after bariatric surgery not only induces a simple mass-related adaptation in gait but also achieves mechanical plasticity in gait strategy.

Kinematic and kinetic changes in obese gait in bariatric surgery-induced weight loss.

This study examines the effects of a radical bariatric surgery-induced weight loss on the gait of obese subjects. We performed a three-dimensional motion analysis of lower limbs, and collected force platform data in the gait laboratory to calculate knee and hip joint moments. Subjects (n=13) performed walking trials in the laboratory before and 8.8 months (SD 4.2) after the surgical procedure at two gait speeds (1.2m/s and 1.5m/s). The average weight loss was 26.7kg (SD 9.2kg), corresponding to 21.5% (SD 6.8%) of the initial weight. We observed a decrease in step width at both gait speeds, but no changes in relative double support or swing time or stride length. A significant decrease was noted in the absolute values of peak knee abductor, peak knee flexor and peak hip extensor moments. However, the moment values normalized by the body weight and height remained unchanged in most cases. Thus, we conclude that weight loss reduces hip and knee joint moments in proportion to the amount of weight lost.

Postural control and thigh muscle activity in men with knee osteoarthritis.

The aim of this study was to examine the standing balance and the function of vastus medialis (VM) and biceps femoris (BF) muscles with surface electromyography (EMG). Fifty-four subjects with uni- or bilateral knee osteoarthritis (OA) (aged 50-69 years) and 53 age-matched randomly selected clinically and radiologically healthy men participated in this study. Postural control was assessed on a force platform with a bipedal stance with eyes open (EO) and closed (EC) and a monopedal stance with EO. The balance parameters, mean sway velocity, velocity along AP and ML axes, elliptical area, standard deviation of center of pressure, average radial displacement, mean frequency and frequency domain balance parameters and different power spectral density frequency bands were determined. Root mean square (RMS) for EMG amplitude, mean EMG frequency (f(EMG,mean)) and median EMG frequency (f(EMG,med)) of motor unit activity were calculated from the normalized EMG data. During bipedal stance with EC and EO, there were no significant differences in balance parameters between groups, but during bipedal stance with EO, the RMS in VM was about 56% higher (p<0.05) in subjects with knee OA than in the control subjects and the values of f(EMG,mean) and f(EMG,med) were about 48% higher (p<0.05) in control subjects than subjects with knee OA. It is concluded that subjects with knee OA do not have any standing balance deficit, but they do exhibit increased muscle activity in VM muscle compared to control subjects.

Physical function and properties of quadriceps femoris muscle in men with knee osteoarthritis.

OBJECTIVES: To examine the objective physical function of the lower extremities, to measure the properties of quadriceps femoris muscle (QFM), and to assess subjective disabilities in men with knee osteoarthritis (OA) and to compare the results with those obtained from age- and sex-matched control subjects. DESIGN: Cross-sectional study. SETTING: Rehabilitation clinic in a university hospital. PARTICIPANTS: Male volunteers (n=54) (age range, 50-69y) with knee OA and randomly selected healthy, age- and sex-matched control subjects (n=53). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Physical function evaluated with a test battery including the QFM composition measurement, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the RAND 36-Item Short-Form Health Survey, version 1.0. RESULTS: Knee OA patients had 13% to 26% poorer (P range, .050-.001) physical function and muscle strength compared with the controls. There were also significant differences in QFM composition. WOMAC (P range, .050-.001) and muscle strength (P<.001) associated with physical function tests, but subjective pain correlated with neither physical function nor muscle strength in knee OA patients. The radiographic knee OA grade did not have any significant effect on physical function, but passive knee motion, knee extension strength, and WOMAC were related to the severity of the disease (P<.05). CONCLUSIONS: The patients with knee OA exhibited impaired physical function and muscle strength and QFM composition compared with healthy controls. The severity of radiographic knee OA clearly had adverse effects on functional ability at the later stages of the disease. The results highlight the effect of QFM strength on physical function as well as the importance of patient's subjective and objective physical function when deciding on knee OA treatment policy.