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  • Author: Tina L. Skinner x
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Kirstin S. Morris, Mark A. Osborne, Megan E. Shephard, David G. Jenkins and Tina L. Skinner

Purpose:

The contributions of the limbs to velocity and metabolic parameters in front-crawl swimming at different intensities have not been identified considering both stroke and kick rate. Consequently, velocity, oxygen uptake (V̇O2), and metabolic cost of swimming with the whole body (swim), the upper limbs only (pull), and lower limbs only (kick) were compared with stroke and kick rate controlled.

Methods:

Twenty elite swimmers completed six 200-m trials: 2 swim, 2 pull, and 2 kick. Swim trials were guided by underwater lights at paces equivalent to 65% ± 3% and 78% ± 3% of participants’ 200-m-freestyle personal-best pace; paces were described as low and moderate, respectively. In the pull and kick trials, swimmers aimed to match the stroke and kick rates, respectively, recorded during the swim trials. V̇O2 was measured continuously, with velocity and metabolic cost calculated for each 200-m effort.

Results:

The velocity contribution of the upper limbs (mean ± SD; low 63.9% ± 6.2%, moderate 59.6% ± 4.2%) was greater than that of the lower limbs to a large extent at both intensities (low ES = 4.40, moderate ES = 4.60). The V̇O2 used by the upper limbs differed between the intensities (low 55.5% ± 6.9%, moderate 51.4% ± 4.0%; ES = 0.74). The lower limbs were responsible for a greater percentage of the metabolic cost than the upper limbs at both intensities (low 56.1% ± 9.5%, ES = 1.30; moderate 55.1% ± 6.6%, ES = 1.55).

Conclusions:

Implementation of this testing protocol before and after a pull- or kick-training block will enable sport scientists to determine how the velocity contributions and/or metabolic cost of the upper- and lower-limb actions have responded to the training program.

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Nicolas Aguilar-Farias, Wendy J. Brown, Tina L. Skinner and G.M.E.E. (Geeske) Peeters

Background: The purpose was to assess metabolic equivalent (MET) values of common daily activities in middle-age and older adults in free-living environments and compare these with MET values listed in the compendium of physical activities (CPA). Methods: Sixty participants (mean age = 71.5, SD = 10.8) completed a semistructured protocol of sitting, lying, self-paced walking, and 4 self-selected activities in their residences. Oxygen consumption was measured using portable indirect calorimetry, to assess METs for each activity relative to VO2 at rest (VO2 during activity/VO2 at rest). Measured MET values for 20 different activities were compared with those in the CPA, for the total sample and for participants aged 55–64, 65–74, and 75–99 years. Results: Measured METs for sitting, walking, sweeping, trimming, and laundry were significantly different from the CPA values. Measured MET values for sedentary activities were lower in all age groups, and those for walking and household activities were higher in the youngest age group, than the CPA values. For gardening activities, there was a significant decline in measured METs with age. Conclusions: Some measured MET values in older people differed from those in the CPA. The values reported here may be useful for future research with younger, middle-age, and older-old people.

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Mia A. Schaumberg, Lynne M. Emmerton, David G. Jenkins, Nicola W. Burton, Xanne A.K. Janse de Jonge and Tina L. Skinner

Purpose: Menstruation and menstrual symptoms are commonly cited barriers to physical activity in women. The delay or avoidance of menstruation through extended oral-contraceptive (OC) regimens may mitigate these barriers, yet information on menstrual-manipulation practices in young physically active women is sparse. The objective of this study was to investigate prevalence of, and reasons for, menstrual manipulation with OCs in recreationally and competitively active women. Methods: One hundred ninety-one recreationally active (self-reported moderate to vigorous physical activity 150–300 min/wk) women (age 23 ± 5 y), 160 subelite recreationally active (self-reported moderate to vigorous physical activity >300 min/wk) women (age 23 ± 5 y), and 108 competitive (state-, national- or international-level) female athletes (age 23 ± 4 y) completed a self-administered questionnaire assessing OC-regimen habits and reasons for manipulation of menstruation. Results: The majority (74%) of OC users reported having deliberately manipulated menstruation at least once during the previous year, with 29% reporting having done so at least 4 times. Prevalence of menstrual manipulation (at least once in the previous year) was not different between competitive athletes, subelite recreationally active women, and recreationally active women (77% vs 74% vs 72%; P > .05). The most cited reasons for manipulating menstruation were special events or holidays (rated by 75% as important/very important), convenience (54%), and sport competition (54%). Conclusions: Menstrual manipulation through extended OC regimens is common practice in recreationally and competitively active young women, for a range of reasons relating to convenience that are not limited to physical activity. This strategy may help reduce hormone-related barriers to exercise participation, thereby positively affecting participation and performance.