Acute Effects of Whole-Body Vibration Alone or in Combination With Maximal Voluntary Contractions on Cardiorespiratory, Musculoskeletal, and Neuromotor Fitness in Obese Male Adolescents

Development of stratified normative data and reference equations for the timed up and down stairs test for healthy children 6-14 years of age

OBJECTIVES

To generate normative data on healthy children aged 6-14 years for the timed up and down stairs (TUDS) test, and to provide reference equations.

DESIGN AND SETTING

Cross-sectional study at two primary schools.

PARTICIPANTS

Healthy children 6-14 years of age.

MAIN OUTCOMES MEASURES

Anthropometric data and Minnesota Leisure-Time Physical Activity Questionnaire from children were collected before the start of the TUDS test. Heart rate, blood pressure and perceived exertion were measured at the beginning and at the end of the test. Two trials of the TUDS test were performed with 15-minute of rest on the same day and the better of the two trials was used in the analyses. The reference equations were established using the anthropometric variables as possible predictors of the TUDS test.

RESULTS

Two hundred fifty eight children (125 boys and 133 girls) were assessed. The mean TUDS test score decreased significantly from 6 to 14 years of age in boys and girls alike, with statistically significant differences between the three age range groups. A significant difference was found between girls and boys in TUDS test score. The 56% of the variation in TUDS test score could be explained by age, height, and weight in boys [TUDS_sec score=(9.967-(0.182×Age_years)+(0.025×Weight_kg)-(2.546×Height_m)], while 50% could be explained in girls [TUDS_sec score=10.553-(0.194×Age_years)+(0.019×Weight_kg)-(2.406×Height_m)]. The inclusion of physical level activity increased the variability explained (boys: 59%; girls: 51%).

CONCLUSIONS

TUDS score improved as the age of the children increased, with boys achieving better values than girls within each age group. TUDS test score can be easily predicted from age, height, and weight. The inclusion of the child's physical activity level increased the variance explained by the equation.

Acute Effects of Whole-Body Vibration Exercises at 2 Different Frequencies Versus an Aerobic Exercise on Some Cardiovascular, Neuromotor and Musculoskeletal Parameters in Adult Patients With Obesity

Whole-body vibration exercise (WBVE), a nonimpact, viable and safe type of exercise, has been reported to be useful in the physical rehabilitation of obesity. Aim of the study was to compare the acute effects of WBVE with a session of walking and running (AER) on cardiovascular, neuromotor and musculoskeletal parameters in obese subjects. Sixteen adult obese subjects performed 3 tests (WBVE at 30 and 45 Hz, AER) randomly in different days. An increase in heart rate was recorded after AER and 45 Hz WBVE (p < 0.001), while only AER increased systolic (p = 0.003) and diastolic blood pressure (p = 0.004) and ratings of perceived exertion (p < 0.001). All 3 exercises determined lactate increase [AER p < 0.001, 45 Hz (p = 0.04), 30 Hz (p = 0.03) WBVE] and sit-and-reach (AER p = 0.002, 45 and 30 Hz WBVE p < 0.001) and fingertip-to-floor improvements (AER p = 0.003, 30 and 45 Hz WBVE p < 0.001), while only 30 Hz WBVE determined improvement in stair climbing test (p < 0.05). Considering the lack of effects of 30 Hz WBVE on the cardiovascular system and fatigue and its positive effect on flexibility and muscle power, this procedure can be considered an appropriate exercise protocol for the obese population.

Individualized Whole-Body Vibration: Neuromuscular, Biochemical, Muscle Damage and Inflammatory Acute Responses

Objective. We aimed to investigate the acute residual hormonal, biochemical, and neuromuscular responses to a single session of individualized whole-body vibration (WBV) while maintaining a half-squat position. Methods. Twenty male sport science students voluntarily participated in the present study and were randomly assigned to an individualized WBV group (with the acceleration load determined for each participant) or an isometric group (ISOM). A double-blind, controlled parallel study design with repeated measures was employed. Results. Testosterone and growth hormone increased significantly over time in the WBV group (P < .05 and P < .01, respectively; effect size [ES] ranged from 1.00 to 1.23), whereas cortisol increased over time in both groups (P < .01; ES ranged from 1.04 and 1.36). Interleukin-6 and creatine kinase increased significantly over time only in the WBV group (P < .05; ES = 1.07). The maximal voluntary contraction decreased significantly over time in the ISOM group (P = .019; ES = 0.42), whereas in the WBV group, the decrease did not reach a significant level (P = .05). The ratio of electromyographic activity and power decreased significantly over time in the WBV group (P < .01; ES ranged from 0.57 to 0.72). Conclusion. Individualized WBV increased serum hormonal concentrations, muscle damage, and inflammation to levels similar to those induced by resistance training and hypertrophy exercises.

Effect of Multi-Frequency Whole-Body Vibration on Muscle Activation, Metabolic Cost and Regional Tissue Oxygenation

Prolonged immobilization from a critical illness can result in significant muscle atrophy. Whole-body vibration (WBV) could potentially attenuate the issue of muscle atrophy; however, there exists no device that could potentially provide WBV in supine position that is suitable for critically ill patients. Hence, the purpose of this study was to develop a new wearable suit, called therapeutic vibration device (TVD), that can provide WBV in supine position and test its effects on physiologic markers of physical activity including muscle activation, oxygen consumption (VO₂), and regional hemoglobin oxygen saturation (rSO₂). The prototype TVD delivered multi-frequency WBV axially to 19 healthy participants in supine position for 10 minutes simultaneously at 25 Hz/4.2 g_rms on the feet and 15 Hz/0.7 g_rms on the shoulders. Muscle activation was recorded by electromyography (EMG), VO₂ was measured by indirect calorimetry and rSO₂ was recorded by near-infrared spectroscopy. Recordings were collected from each participant from multiple body locations, on three separate days, at baseline and during the intervention. Acceleration was also recorded to gain insight into transmissibility and coherence. Repeated-measures ANOVA using Bonferroni correction revealed that the muscle activity significantly increased by 4% - 62% (p < 0.05), VO₂ improved by 22.3% (p < 0.05) and rSO₂ increased by 1.4% - 4.5% (p < 0.05) compared to baseline. WBV provided by the TVD is capable of producing physiologic responses consistent with mild physical activity. Such effects could potentially be valuable as an adjunct to physical therapy for early mobilization to prevent atrophy occurring from prolonged immobilization.