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  • Author: Elizabeth Johnson x
  • Sport and Exercise Science/Kinesiology x
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Thomas Zochowski, Elizabeth Johnson and Gordon G. Sleivert

Context:

Warm-up before athletic competition might enhance performance by affecting various physiological parameters. There are few quantitative data available on physiological responses to the warm-up, and the data that have been reported are inconclusive. Similarly, it has been suggested that varying the recovery period after a standardized warm-up might affect subsequent performance.

Purpose:

To determine the effects of varying post-warm-up recovery time on a subsequent 200-m swimming time trial.

Methods:

Ten national-caliber swimmers (5 male, 5 female) each swam a 1500-m warm-up and performed a 200-m time trial of their specialty stroke after either 10 or 45 min of passive recovery. Subjects completed 1 time trial in each condition separated by 1 wk in a counterbalanced order. Blood lactate and heart rate were measured immediately after warm-up and 3 min before, immediately after, and 3 min after the time trial. Rating of perceived exertion was measured immediately after the warm-up and time trial.

Results:

Time-trial performance was significantly improved after 10 min as opposed to 45 min recovery (136.80 ± 20.38 s vs 138.69 ± 20.32 s, P < .05). There were no significant differences between conditions for heart rate and blood lactate after the warm-up. Pre-time-trial heart rate, however, was higher in the 10-min than in the 45-min rest condition (109 ± 14 beats/min vs 94 ± 21 beats/min, P < .05).

Conclusions:

A post-warm-up recovery time of 10 min rather than 45 min is more beneficial to 200-m swimming time-trial performance.

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C. Shanthi Jacob Johnson, Anita M. Myers, Lynn M. Scholey, Elizabeth V. Cyarto and Nancy A. Ecclestone

The Home Support Exercise Program (HSEP) targets frail older adults. After a 4-hr training workshop, home-support workers (HSWs) encourage clients to do a simple, progressive set of 10 exercises during regular visits. Exercise compliance and functional performance were examined in 60 clients who received the HSEP, compared with 38 clients whose HSWs had not received HSEP training. Both groups were primarily female, average age 82, and many of them used walking aids. The 40 HSEP clients who continued with the program over 4 months showed good compliance and significant improvement on several indicators: timed up-and-go, sit-to-stand, 6-min walk, balance confidence, and well-being. Conversely, the comparison group declined on several measures. The findings support the effectiveness of the HSEP, as well as the importance of regular and ongoing support from HSWs for this population.

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Richard Suminski, Terry Presley, Jason A. Wasserman, Carlene A. Mayfield, Elizabeth McClain and Mariah Johnson

Background:

More than 200,000 children each year are treated at emergency departments for injuries occurring on playgrounds. Empirically derived data are needed to elucidate factors associated with playground safety and reduce injury rates.

Objective:

Determine if neighborhood, park and playground characteristics are significantly associated with playground safety.

Methods:

A 24-item report card developed by the National Program for Playground Safety was used to assess playground safety at 41 public parks in a small to midsized, Midwestern city. Trained assessors evaluated the parks and playgrounds in June/July and used a standardized method to count the numbers of users. Data from the 2010 U.S. Census were used to describe the neighborhoods surrounding the parks.

Results:

The average safety score for all playgrounds was 77.4% which denotes acceptable safety levels. However, 17.1% of the playgrounds were potentially hazardous and in need of corrective measures. Playgrounds were safer in neighborhoods with more youth (< 18 years of age) and educated adults and in parks with better quality features. Playgrounds with fewer amenities were relatively less safe.

Conclusions:

Park safety levels need to be improved to reduce the risk of physical injuries. Future studies examining cause-effect associations between environmental features and playground safety are warranted.

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Garry D. Wheeler, Robert D. Steadward, David Legg, Yesahayu Hutzler, Elizabeth Campbell and Anne Johnson

This study aimed to examine the transferability of a personal investment process of disability sport to athletes from the USA, UK, Canada, and Israel. Initiation, competition, and retirement experiences of 40 athletes were examined. Results corroborate previous findings on athletes with and without disabilities and reveal no differences in major themes among athletes from different countries. A revised personal investment process model is proposed. Athletes with a disability should receive some form of preparatory counseling support before and after retirement. Difficulties during the transition to retirement are generally associated with overcommitment, ego identity in sport, and exclusion of other aspects of life (Baille, 1993; Blinde & Stratta, 1992; Hill & Lowe, 1974; Sinclair & Orlick, 1993). Factors associated with successful transition include sense of accomplishment, voluntary retirement, degree of ego involvement and commitment, anticipatory socialization, planning, social support structures, adequate financial support, and maintenance of outside interests (Baille, 1993; Sinclair & Orlick, 1993; Werthner & Orlick, 1986).

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Liam Johnson, Patricia K. Addamo, Isaac Selva Raj, Erika Borkoles, Victoria Wyckelsma, Elizabeth Cyarto and Remco C. Polman

There is evidence that an acute bout of exercise confers cognitive benefits, but it is largely unknown what the optimal mode and duration of exercise is and how cognitive performance changes over time after exercise. We compared the cognitive performance of 31 older adults using the Stroop test before, immediately after, and at 30 and 60 min after a 10 and 30 min aerobic or resistance exercise session. Heart rate and feelings of arousal were also measured before, during, and after exercise. We found that, independent of mode or duration of exercise, the participants improved in the Stroop Inhibition task immediately postexercise. We did not find that exercise influenced the performance of the Stroop Color or Stroop Word Interference tasks. Our findings suggest that an acute bout of exercise can improve cognitive performance and, in particular, the more complex executive functioning of older adults.

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Matthew W. Hoon, Andrew M. Jones, Nathan A. Johnson, Jamie R. Blackwell, Elizabeth M. Broad, Bronwen Lundy, Anthony J. Rice and Louise M. Burke

Context:

Beetroot juice is a naturally rich source of inorganic nitrate (NO3 ), a compound hypothesized to enhance endurance performance by improving exercise efficiency.

Purpose:

To investigate the effect of different doses of beetroot juice on 2000-m ergometer-rowing performance in highly trained athletes.

Methods:

Ten highly trained male rowers volunteered to participate in a placebo-controlled, double-blinded crossover study. Two hours before undertaking a 2000-m rowing-ergometer test, subjects consumed beetroot juice containing 0 mmol (placebo), 4.2 mmol (SINGLE), or 8.4 mmol (DOUBLE) NO3 . Blood samples were taken before supplement ingestion and immediately before the rowing test for analysis of plasma [NO3 ] and [nitrite (NO2 )].

Results:

The SINGLE dose demonstrated a trivial effect on time to complete 2000 m compared with placebo (mean difference: 0.2 ± 2.5 s). A possibly beneficial effect was found with DOUBLE compared with SINGLE (mean difference –1.8 ± 2.1 s) and with placebo (–1.6 ± 1.6 s). Plasma [NO2 ] and [NO3 ] demonstrated a dose-response effect, with greater amounts of ingested nitrate leading to substantially higher concentrations (DOUBLE > SINGLE > placebo). There was a moderate but insignificant correlation (r = –.593, P = .055) between change in plasma [NO2 ] and performance time.

Conclusion:

Compared with nitratedepleted beetroot juice, a high (8.4 mmol NO3 ) but not moderate (4.2 mmol NO3 ) dose of NO3 in beetroot juice, consumed 2 h before exercise, may improve 2000-m rowing performance in highly trained athletes.