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- Cook, C. J., et al.
(författare)
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Morning based strength training improves afternoon physical performance in rugby union players
- 2014
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Ingår i: Journal of Science and Medicine in Sport. - : Elsevier BV. - 1878-1861 .- 1440-2440. ; 17:3, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo determine if a morning training session could alter afternoon physical performance. Moreover, as testosterone (T) and cortisol (C) concentrations are significant predictors of physical performance, and both show circadian declines across the day, we examined the effects of morning training on diurnal T and C responses. DesignEighteen semi-professional rugby union players completed this randomised and counter-balanced study. MethodsFollowing morning saliva collection (0900. h), players completed a control (rested), Sprint (5 × 40 m) or Weights (3 repetition-maximum [RM] bench press and squat) trial. In the afternoon (15:00. h) of each trial, a further saliva sample was collected before players completed a performance test (3RM back squat and bench press, 40. m sprint, countermovement jump [CMJ]). ResultsSalivary T concentrations declined from am to pm under Control and Sprint, but not under Weights. Delta T, from am to pm, was greater under Control (-10.9±2.4pgml-1) compared to Sprints (-6.2±7.1pgml-1) and Weights (-1.2±5.5pgml-1) (p≤0.001). Delta C, from am to pm, was greater under Control compared to both Sprint and Weights (p<0.05). Players elicited better CMJ peak power, 40-m time, 3RM bench and squat performance under Weights compared with Control and Sprint (p<0.05). Faster 40-m times were seen under Sprint, when compared to Control (p<0.05). ConclusionsPerforming morning strength training is associated with improved physical performance in the afternoon. Additionally, the circadian decline in T concentrations appeared offset by morning training. However, it is unclear if T concentrations are, in part, causal of these improved responses or simply a reflective marker. © 2013 Sports Medicine Australia.
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- Duberg, Anna, 1976-, et al.
(författare)
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Adolescent girls with internalizing problems : Can dance intervention improve health? A randomized, controlled trial with cost-utility analysis
- 2012
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Ingår i: Journal of Science and Medicine in Sport. - : Elsevier. - 1440-2440 .- 1878-1861. ; 15:Suppl. 1, s. S345-S346
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: The increasing prevalence of psychological health problems among adolescent girls is alarming. Knowledge of beneficial effects of physical activity on psychological health are widespread. Dance is a popular form of exercise also known to increase a sense of self-control which can contribute to reduced stress. The purpose of this study was to investigate if dance intervention for adolescent girls with internalizing problems influenced self-rated health. A secondary aim was to assess the cost-effectiveness of the intervention in addition to usual school health services, compared with usual school health services alone.Methods: Randomized controlled intervention trial with follow-up measures of self-rated health at 8, 12 and 20 months after baseline. A total of 112 girls, 13–18 years old, with internalizing problems, i.e. stress and psychosomatic symptoms, were randomized to intervention group or control group. The intervention comprised dance classes twice weekly during 8 months. Each dance class lasted 75 minutes and the focus was on the joy of movement, not on performance. Costs for the stakeholder of the intervention, treatment effect and healthcare costs were considered. Gained quality-adjusted life-years (QALY) were used to measure the effects. Quality of life (QOL) was measured with the Health Utility Index Mark 3 (HUI 3). Cost-effectiveness ratios were based on the changes in QALY and net costs for the intervention group compared with the control group. Net monetary benefit (NMB) was also calculated.Results: A year after baseline 65% of the girls in the intervention group and 32% of the girls in the control group had increased their self-rated health. The differences in change score between groups were significant at all follow-ups. After 8-months U = 895.5 (P = .037), after 12-months U = 680.0 (P = .001), and after 20-months U = 801 (P = .022).Cost effectiveness showed that after 20 months, QOL had increased by 0.083 units more in the intervention group than in the control group (P = .04), translating to 0.095 gained QALY. The cost-effectiveness ratio was $7187.4 and the NMB was $3846.0 (Willingness to pay $50 000 for a gained QALY).Discussion: This study suggests that an 8-month dance intervention can improve self-rated health for adolescent girls with internalizing problems. The improvement remained a year after the intervention. The intervention in addition to usual school health services showed cost-effectiveness compared with usual school health services alone. The cost-effectiveness ratio was far below the recommended threshold value.
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- Ivarsson, Andreas, et al.
(författare)
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Psychosocial stress as a predictor of injury in elite junior soccer : A latent growth curve analysis
- 2014
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Ingår i: Journal of Science and Medicine in Sport. - Chatswood : Elsevier BV. - 1440-2440 .- 1878-1861. ; 17:4, s. 366-370
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate by use of a latent growth curve analysis framework whether athletes' individual levels and changes in hassle and uplift levels over a 10-week period could predict injury outcome in an elite junior soccer population. Design: A prospective design with repeated measurement points. Methods: Participants were 101 Swedish elite junior soccer players (67 males and 34 females). Ten sets of measures were taken on a weekly basis during which participants completed the Hassles and Uplifts Scale (HUS). Latent growth curve models were used to examine whether the level and change in psychological stress could predict the frequency of injury over the 10-week period. Results: The results show that injury occurrence was significantly associated with both the initial level of daily hassle and the change in daily hassle. High initial daily hassle levels and a smaller decrease in daily hassles were associated with injury occurrence. Moreover, injury occurrence was significantly associated with a greater decrease in daily uplift. Conclusions: The findings highlight the importance of focusing on state variables using prospective designs and appropriate analysis of within-person change to detect complex and dynamic associations across time in injury-prediction research. (C) 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
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- McGawley, Kerry, 1978-, et al.
(författare)
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The effect of short-term sprint-interval training on repeated-sprint ability
- 2010
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Ingår i: Journal of Science and Medicine in Sport. - 1440-2440 .- 1878-1861. ; 13:6, s. e52-
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The purpose of the present study was to investigate whether short-term sprint-interval training (SIT) would enhance repeated-sprint ability (RSA) via improvements in power output, work decrement and oxygen uptake in recovery. Methods: Eight male, recreational team-sport players (mean±SD age: 21±2 y, body mass: 78.1±4.3 kg) completed a repeated-sprint test (RST) and a graded cycle test to exhaustion for the evaluation of VO2max before and after two weeks of SIT. The RST consisted of 7×5-s cycle sprints interspersed with 25 s of passive recovery. Peak power output (PP), mean power output (MP), decrement in MP (MPdec) and total work done (TWD) were recorded. In addition, VO2 was measured during the 25-s passive recovery periods between each sprint. The SIT involved six sessions (three sessions per week) of 4, 5 or 6 × 30-s, all-out sprints interspersed with 4.5 min of light recovery. The number of sprint repetitions increased by one after every two training sessions. Results and conclusion: Although there was no change in PP for any of the 7×5-s sprints following SIT (P > 0.05) there were significant increases in MP for each of the 7×5-s sprints (P < 0.05) and in TWD during the RST (mean±SD: 7.6±3.0 versus 29.4±2.6 kJ from pre- to post-training; P < 0.05). The MPdec decreased from 12.4 ±6.8 to 7.4±2.9% from pre- to post-training (P < 0.05) but VO2 between sprints was unchanged (P > 0.05). Furthermore, VO2max was not different following training (45.7±7.7 versus 45.0±5.4 mLkg-1 min-1 from pre- to post-training; P > 0.05). These findings suggest that short-term SIT may be an effective intervention for improving RSA within team-sport athletes via increases in work done during each sprint and reductions in the decrement in work done over a series of sprints. This does not appear to be due to greater oxygen uptake during the 25-s recovery periods between sprints or improvements in peak power. Other metabolic adaptations to SIT that maintain muscle force during high-intensity exercise may explain the current findings.
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- McGawley, Kerry, 1978-, et al.
(författare)
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The effect of water immersion on the recovery of team-sport-specific exercise
- 2010
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Ingår i: Journal of Science and Medicine in Sport. - 1440-2440 .- 1878-1861. ; 13:6, s. e51-
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The purpose of the present study was to examine the effects of two hydrotherapy techniques, cold water immersion (CWI) and contrast-water therapy (CWT), on the recovery of team-sport-specific exercise tests following muscle-damaging exercise. Methods: Seven male, team-sport players (mean±SD age: 21±2 y, body mass:76.8±7.2 kg) completed a preliminary familiarisation trial for three team-sport-specific exercise tests (TESTS), which included an all-out 30-m sprint test, two agility T-tests (left and right) and a vertical jump test. Three experimental trials were subsequently carried out, each separated by one week, using a counter-balanced cross-over design. On each visit a resting fingertip blood sample and a rating of perceived muscle soreness (PMS) was collected. Participants then performed the TESTS, followed by a 5-min rest period. A repeated sprint exercise (RSE) protocol was then performed to induce muscle damage, which comprised of 15 × 30-m sprints with a 10-m deceleration zone. Sprints were separated by 1 min. A second fingertip blood sample and PMS score was collected immediately after the RSE and a second set of TESTS were performed 10 min after the RSE. Participants then received either CWI, CWT or no water immersion (CON). The next day (24–28 h later) a final fingertip blood sample and PMS score was collected and a final set of TESTS were completed. Results and conclusion: There were no changes in plasma CK over time and no significant interaction effects between the three intervention groups (P > 0.05). The PMS increased from baseline to 24–28 h in the CON group (P < 0.05), but was not different from baseline at 24–28 h for the CWI or CWT groups (P > 0.05). The PMS was significantly higher for CON compared with CWT after 24–28 h (P < 0.05), but no other differences were found between groups (P > 0.05). There were no significant differences in performance during the TESTS between the three intervention groups across any of the three time points (pre RSE, post RSE or after 24–28 h; P > 0.05). These data suggest that the RSE may not have induced sufficient muscle damage to increase plasma CK levels, which may explain why the recovery interventions did not have a significant effect on performance of the TESTS. However, the differences in PMS changes indicate that hydrotherapy may be effective in suppressing the perception of muscle soreness when biochemical and performance markers are unchanged.
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