Pierre-Louis Bernard

Effects of a physical activity program on postural stability in older people

Background and aims: The objective of this non-randomized study was to determine the influence of a specific physical activity program on the postural stability of older people. Methods: Seventy-four subjects (72.4±0.7 yrs) participated in an individualized three-month physical activity program designed to improve posture, balance and mobility — the PBM program. Sessions were held twice weekly. Postural stability was assessed using a force platform, subjects being in static and dynamic conditions, and with open and closed eyes. Changes in stabilometric parameters (Sway area, ML mean, AP mean, Total length, ML length and AP length) of the intervention group were compared to those of 14 control subjects (71.8±1.5 years). Results: A two-way analysis of variance with repeated measures did not show any significant post-program change in postural stability in the hard floor condition. In contrast, Sway area (p<0.0005), Total length (p<0.001) and AP length (p<0.01) were significantly reduced after the training program in the foam floor condition, with open and closed eyes. In addition, in the mediolateral axis condition and with closed eyes, AP length in the intervention group was significantly reduced (p<0.01, and in the antero-posterior axis condition with both open and closed eyes, Sway area (p<0.0005), Total length (p<0.0005) and AP length (p<0.05) decreased significantly. Conclusions: As shown by the results in the foam floor and dynamic conditions, our individualized physical activity program improved the postural stability of older people when the standing position was challenged. However, the lack of significant results for the hard floor condition suggests that three months is not sufficient to improve static balance. The PBM physical activity program can be used for balance training in older people, but further studies are required to determine the time needed to effect improvements in static balance in this population.

Validation of an incremental field test for the direct assessment of peak oxygen uptake in wheelchair-dependent athletes

The aim of this study was to validate an incremental field test performed by wheelchair-dependent (WD) athletes. Nine male paraplegic subjects (mean age: 28.9±4.2 years) performed an incremental field test (FT) and a comparable laboratory test (LT) with their own usual wheelchairs. Both tests started with an initial speed of 4 km.hr-1 and increased by increments of 1 km.hr-1 every minute until volitional exhaustion. The FT was an adapted Léger and Boucher test (ALBT) and was conducted on a 400 m tartan field marked-off every 50 m with pylons. Ventilatory data were collected every 15 s using a portable telemetric system (Cosmed K2, JFB International, Italy). The LT was performed on an adapted treadmill (Sopur, Germany) and ventilatory data were collected every minute using a breath-by-breath automated system (CPX, Medical Graphics, MN, USA). The LT and the FT were not significantly different for duration (8 min 50 ±1 min 24 vs 9 min 55 ±29 s), percentage of maximal heart rate (HR, 86.2±3.9 vs 89.7±5.3%), maximal minute ventilation (Ve, 101.6±28.5 vs 96.8±28.2 l.min-1), and peak oxygen uptake (Vo2 peak, 39.7 + 7.3 vs 36.1 + 5.8 ml.kg-1.min-1) assessed with the CPX and the K2, respectively. We concluded that the FT proposed in the present study is a valid test for direct Vo2 peak assessment in wheelchair athletes using a portable Vo2 telemetric system. Nonetheless, the Léger and Mercier model equation did not accurately predict Vo2 max and further investigation is needed to determine a valid Vo2 max prediction equation for these subjects during the FT.

Reproducibility of the Adapted Leger and Boucher Test for wheelchair-dependent athletes

Study design: This study analyzed the reproducibility of a field test. In a previous study, we showed that this test, the Adapted Leger and Boucher Test (ALBT), was progressive and maximal. The Leger and Boucher predictive equation for able-bodied subjects was not accurate for WD athletes, however, and a new predictive equation is needed.Objectives: To determine the reproducibility of an adapted incremental field test for wheelchair-dependent (WD) athletes.Setting: France at Montpellier.Methods: The proposed protocol was conducted on a 400 m track. Eight male paraplegics (mean age: 30.8±5.1 years) performed the test three times in the same conditions, ie same time of day, same wheelchair, same material. Maximal heart rate (HRmax) and maximal speed (Smax) were measured.Results: We found no significant differences (P>0.05) between tests for either variable. The Bland and Altman graphic analyses showed a good reproducibility for both variables. Lastly, the reproducibility coefficients of HRmax and Smax were very low (2% and 1%, respectively).Conclusion: The ALBT is reproducible concerning measurements of HRmax and Smax. A valid predictive equation of maximal oxygen uptake from the Smax is now needed for WD athletes during this field test.