Acute effect of whole-body vibration on sprint and jumping performance in elite skeleton athletes.

The winter sliding sport known as skeleton requires athletes to produce a maximal sprint followed by high speed sliding down a bobsled track. Athletes are required to complete the course twice in 1 hour and total time for the 2 runs determines overall ranking. The purpose of this investigation was to examine the effect of whole-body vibration (WBV) on lower body power to explore the utility of WBV as an ergogenic aid for skeleton competition. Elite skeleton athletes (1 male and 6 females) completed an unloaded squat jump (SQJ) immediately followed by 2 countermovement jumps (CMJs) and a maximal 30-m sprint before and after WBV or no vibration (CON) using a crossover design. The second 30-m sprint was slower following both CON (1.4% decrement; p = 0.05) and WBV (0.7% decrement; p = 0.03). Mean vertical velocity was maintained following WBV in the SQJ but decreased following CON (p = 0.03). There was a trend for athletes to commence the SQJ from a higher starting stance post-WBV compared to CON (p = 0.08). WBV decreased total vertical distance traveled compared to CON in the SQJ (p = 0.006). WBV had little effect on peak velocity, jump height, dip, and peak acceleration or any CMJ parameters. When sprint athletes' warm up and perform maximal jumps and a 30-m sprint with 15-20 minutes of recovery before repeating the sequence, the second series of performances tend to be compromised. However, when WBV is used before the second series of efforts, some aspects of maximal jumping and sprinting appear to be influenced in a beneficial manner. Further research is required to explore whether WBV can improve the second sprint for athletes in actual competition and/or what sort of WBV protocol is optimal for these populations.

Effect of number of home exercises on compliance and performance in adults over 65 years of age.

BACKGROUND AND PURPOSE: There is limited research on the effects of the number of exercises a person is told to perform on compliance and performance, as defined by cueing requirements, correct alignment, and quality of movement. Some studies of medication suggest that compliance decreases as the number of medications increases. The purpose of this study was to determine whether older adults comply and perform better (ie, requiring less cueing, exhibiting correct alignment, and exhibiting controlled, coordinated, and continuous movements) when they are asked to do 2, 5, or 8 exercises. SUBJECTS: Subjects were 11 women and 4 men, aged 67 to 82 years (X=72.8), who were living independently in their communities. METHODS: Subjects were randomly prescribed 2, 5, or 8 general strengthening home exercises. They were instructed on their exercises at an initial session and asked to record the number of repetitions performed each day in a self-report exercise log. At a return session 7 to 10 days later, subjects were scored on their performance of the prescribed exercises using a newly designed assessment tool. RESULTS: The group that was prescribed 2 exercises performed better, as defined by their performance tool score, than the group that was prescribed 8 exercises. The group that was prescribed 5 exercises was not different from the groups that performed 2 or 8 exercises. No differences were found among groups regarding the self-report measurement of compliance. There was a moderate correlation between performance scores and the self-report percentage rates. CONCLUSION AND DISCUSSION: Subjects who were prescribed 2 exercises performed better than subjects who were prescribed 8 exercises. The question of an optimal number of exercises to prescribe to elderly people warrants further study.

On the number of automated timed manual performance trials to administer.

OBJECTIVE: To determine the number of trials needed to obtain satisfactory results when evaluating function in older subjects using the automated version of the Williams short (three-door) Timed Manual Performance (TMP) test. DESIGN: Administration of from one to five trials in succession on a given test date. SETTING: A Continuing Care Retirement Community (CCRC), assisted living centers, nursing homes, and a community residence, all located in central North Carolina. PARTICIPANTS: The subject population consisted of 182 older volunteers, aged 63 to 100 years. One hundred nineteen lived independently in a CCRC, 33 were assisted-living residents, 29 lived in nursing homes, and one lived independently in the community. Each subject was administered at least three trials in succession on his or her first test date; 23 of the independently living CCRC residents were given three trials on a second test date. The community-dwelling volunteer was administered from one to five trials on each of 26 test dates over an approximately 16-month period. MEASUREMENTS: The time it takes to perform five door opening and closing operations as measured by the three-door Cognatemp Automated Timed Manual Performance (ATMP) system. MAIN RESULTS: Average ATMP time for the subjects living independently decreased approximately 10% between the first two trials but negligibly between trials two and three. The more dependent groups continued to improve between trials two and three. The community-dwelling subject tended to improve in the first three or four trials and to decline by the fifth trial. CONCLUSIONS: It is recommended that two trials be administered and the best time used; if neither trial results in a time less than 10 seconds, one or two more trials should be administered. It is generally not necessary nor advantageous to administer more than four trials.