The effect of adding core stability training to a standard balance exercise program on sit to stand performance in older adults: a pilot study.

This study compared sit to stand (STS) performance between older adults in a nine-week training program focusing on core stability exercises to enhance balance and postural control (EB) versus standard balance (SB) exercises. Repetitions in 30 s (STSreps) and kinematic performance (vertical and horizontal momentum, and margin of stability) were measured pre and postintervention in 23 older adults with at least one fall risk factor. Although both groups combined improved STSreps (P = .001) and vertical momentum (.008), a significant between-group difference was observed for completers only (MANCOVA of posttest group differences, with pretest scores as covariates; P = .04). EB demonstrated a greater but nonsignificant improvement in vertical momentum (P = .095). In conclusion, core stability training added to SB did not result in STS reps improvement. Compliance may modify these results and future larger sample studies should evaluate the impact of core stability training on STS biomechanics.

Physiologic responses of competitive Canadian cross-country skiers with disabilities.

OBJECTIVE: To examine the acute cardiorespiratory and metabolic responses in competitive cross-country skiers with disabilities. DESIGN: Cross-sectional comparisons using a select group of Canadian athletes training for the Vancouver 2010 Paralympic Winter Games. SETTING: Canmore Nordic Centre Provincial Park, Canmore, Alberta. PARTICIPANTS: Nine competitive cross-country skiers (4 with visual impairment, 1 with traumatic brain injury, 3 with spinal cord injury, and 1 with cerebral palsy). INTERVENTIONS: Three-minute and 12-minute exercise tests in the standing or sitting skiing position to voluntary fatigue. MAIN OUTCOME MEASURES: Cardiorespiratory responses using a telemetric system to compare the physiologic responses among the athletes with different disabilities. Heart rate (HR) and capillary lactate were measured at 2, 5, and 10 minutes of recovery. RESULTS: The t test results indicated that the peak values of the absolute and relative oxygen uptake (VO2peak), HR, and ventilation rate were significantly higher during the 12-minute compared with the 3-minute protocol during standing skiing. However, the oxygen pulse and ventilatory equivalent for oxygen ratio were not significantly (P > 0.05) different between the 2 protocols. Analysis of variance revealed no significant (P > 0.05) differences among the 3 trials for these peak physiologic responses during sitting skiing. Cross-sectional comparisons of the peak physiologic responses between the standing and sitting skiers indicated significantly (P < 0.05) higher values in the standing compared with the sitting position. Cardiorespiratory respiratory efficiency was significantly (P < 0.05) lower in the sitting compared with the standing position. HR during 10 minutes of recovery was significantly correlated with VO2peak. Pearson correlations were not significant between VO2peak and lactate removal during recovery. CONCLUSION: These descriptive findings during the standing and sitting skiing protocols provide preliminary data that would be useful in testing, training, and classification of competitive skiers with disabilities.

Comparison of a double poling ergometer and field test for elite cross country sit skiers.

BACKGROUND: Sport specific ergometers are important for laboratory testing (i.e. peak oxygen consumption (VO(2))) and out of season training. OBJECTIVES: The purpose of this study was to compare cardiorespiratory variables during exercise on a double poling ergometer to a field test in elite sit skiers. METHODS: Three male and four female athletes from the Canadian National / Developmental team (17-54 years of age, six with complete paraplegia and one with cerebral palsy) completed a field test and a double poling ergometer protocol separated by at least 24 hours. Both protocols consisted of three maximal trials of skiing of three minutes duration separated by 1.5 minutes of rest. A wireless metabolic system and heart rate monitor were used to measure cardiorespiratory responses [peak heart rate, peak VO(2), and peak respiratory exchange ratio (RER)] during each test. Arterialized blood lactate was measured before the beginning of exercise, after each trial and at 5, 10 and 15 minutes post exercise. RESULTS: No significant differences existed between the field and ergometer tests for peak oxygen consumption (VO(2)) (field=34.7±5.5 mL·kg-1·min-1 vs. ergometer=33.4±6.9 mL·kg-1·min-1). Significantly higher peak heart rate and RER were found during the ergometer test. Significantly higher lactates were found during the ergometer test after trial 2 and trial 3. CONCLUSION: The double poling ergometer is similar to a field test for evaluating peak VO(2) in elite cross country sit skiers; however, the ergometer test elicits a higher heart rate and anaerobic response.

The effect of trunk stability training on vertical takeoff velocity.

STUDY DESIGN: Randomized controlled trial with repeated measures. OBJECTIVES: To determine the effect of trunk stability training on vertical takeoff velocity. BACKGROUND: Trunk stability training is commonly used in sports training programs; however, the effects of stability training on performance enhancement are not known. Trunk stability training may provide a more stable pelvis and spine from which the leg muscles can generate action, may better link the upper body to the lower body, or may enhance leg muscle activation, thus promoting optimal force production during sporting activities such as a vertical jump. METHODS AND MEASURES: Fifty-five athletes were randomly assigned to 1 of 4 training groups: trunk stability (TS), leg strength (LS), trunk stability and leg strength (TL), and control (CO). Subjects were tested 3 times: at pretraining, after 3 weeks of training, and after 9 weeks of training. A repeated-measures analysis of covariance (ANCOVA) was used to examine differences among groups for vertical takeoff velocity measured indirectly using a force plate. Pretraining takeoff velocity and body mass were used as covariates. RESULTS: After 3 and 9 weeks, the training groups were not different from each other. After 9 weeks of training, all 3 training groups had a greater takeoff velocity than the control group (P<.05). After 3 weeks of training only the TS group had a greater takeoff velocity than the control group (P<.05). Only the TL group increased significantly in vertical takeoff velocity between the third- and ninth-week testing periods (P<.05). CONCLUSIONS: Nine weeks of trunk stability training was similarly effective in enhancing vertical takeoff velocity as leg strength training or the combination of trunk stability and leg strength training.