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Filho, Edson; di Fronso, Selenia; Forzini, Fabio; Murgia, Mauro; Agostini, Tiziano; Bortoli, Laura; Robazza, Claudio; Bertollo, Maurizio
doi: 10.1080/17461391.2015.1048746pmid: 26279169
AbstractWe sought to examine whether the relationship between recovery–stress factors and performance would differ at the beginning (Stage 1) and the end (Final Stage) of a multi-stage cycling competition. Sixty-seven cyclists with a mean age of 21.90 years (SD = 1.60) and extensive international experience participated in the study. The cyclists responded to the Recovery–Stress Questionnaire for Athletes (RESTQ-Sport) and rated their performance (1 = extremely poor to 10 = excellent) in respect to the first and last stage. Two step-down multiple regression models were used to estimate the relationship among recovery (nine factors; e.g. Physical Recovery, Sleep Quality) and stress factors (10 factors; e.g. Lack of Energy, Physical Complaints), as assessed by the RESTQ-Sport and in relation to performance. Model 1 pertained to Stage 1, whereas Model 2 used data from the Final Stage. The final Model 1 revealed that Physical Recovery (β = .46, p = .01), Injury (β = −.31, p = .01) and General Well-being (β = −.26, p = .04) predicted performance in Stage 1 (R2 = .21). The final Model 2 revealed a different relationship between recovery–stress factors and performance. Specifically, being a climber (β = .28, p = .01), Conflicts/Pressure (β = .33, p = .01), and Lack of Energy (β = −.37, p = .01) were associated with performance at the Final Stage (R2 = .19). Collectively, these results suggest that the relationship among recovery and stress factors changes greatly over a relatively short period of time, and dynamically influences performance in multi-stage competitions.
Shearer, David A.; Jones, Rhys M.; Kilduff, Liam P.; Cook, Christian J.
doi: 10.1080/17461391.2015.1053419pmid: 26255667
AbstractNo published research has assessed sleep patterns of elite rugby union players following match-play. The present study examined sleep patterns of professional rugby union players, prior and post-match-play, to assess the influence of competition. Twenty-eight male rugby union players (24.4 ± 2.9 years, 103.9 ± 12.2 kg) competed in one of four competitive home matches. Player's sleep behaviours were monitored continuously using an Actiwatch® from two days before the match, until three days post-match. Repeated measures of analysis of variance (ANOVA) showed significant differences across the time points measured for time to bed (F = 26.425, η2 = 0.495, p < .001), get up time (F = 21.175, η2 = 0.440, p < .001), time spent in bed (F = 10.669, η2 = 0.283, p < .001), time asleep (F = 8.752, η2 = 0.245, p < .001) and percentage of time moving (F = 4.602, η2 = 0.146 p < .05). Most notable, post hocs revealed a significant increase for time in bed the night before the match (p < .01; 95% CI = 0 : 10–1 : 28 h; 9.7 ± 13.5%) compared with the reference night sleep. Furthermore, time asleep significantly decreased post-match (p < .05; 95% CI = −0:03 to −1:59 h; −19.5 ± 19.8%) compared to two nights pre-match. Across all time points, sleep latency and efficiency for most players were considered abnormal compared to that expected in normal populations. The results demonstrate that sleep that is deprived post-match may have detrimental effects on the recovery process.
García-Ramos, Amador; Feriche, Belén; de la Fuente, Blanca; Argüelles-Cienfuegos, Javier; Strojnik, Vojko; Strumbelj, Boro; Štirn, Igor
doi: 10.1080/17461391.2015.1063699pmid: 26305175
AbstractThe objective of this study was to determine the relationship between different variables measured with a force plate during the swimming start push-off phase and start performance presented by times to 5, 10 and 15 m. Twenty-one women from the Slovenian national swimming team performed two different swim starts (freestyle and undulatory) on a portable force plate to a distance further than 15 m. Correlations between push-off variables and times to 5, 10 and 15 m were quantified through Pearson's product-moment correlation coefficient (r). The variables that significantly correlated (p < .05) to all times measured in the two starts performed were: average horizontal acceleration (freestyle: r = −0.58 to −0.71; and undulatory: r = −0.55 to −0.66), horizontal take-off velocity (freestyle: r = −0.56 to −0.69; and undulatory: r = −0.53 to −0.67) and resultant take-off velocity (freestyle: r = −0.53 to −0.65; and undulatory: r = −0.52 to −0.61). None of the variables derived from the vertical force were correlated to swimming start performance (p > .05). Based on the results of this study, we can conclude that horizontal take-off velocity and average horizontal acceleration (calculated as the average horizontal force divided by swimmer's body mass) are the variables most related to swimming start performance in experienced swimmers, and therefore could be the preferred measures to monitor swimmers’ efficiency during the push-off phase.
Schreiber, Tonja; Allenspach, Philippe; Seifert, Burkhardt; Schweizer, Andreas
doi: 10.1080/17461391.2015.1048747pmid: 26267120
AbstractThis study investigates the changes of the connective tissue in the fingers of performance sport climbers resulting after a minimum of 15 years of climbing. Evaluation was performed by ultrasonography on the palmar side of the fingers (Dig) II–V to measure the thickness of the A2 and A4 annular pulleys, the flexor digitorum superficialis (FDS) and profundus (FDP) tendons and the palmar plates (PP's) of the proximal interphalangeal (PIP) as well as distal interphalangeal (DIP) joint in sagittal and axial direction. Totally, 31 experienced male sport climbers (mean age 37y, 30–48y grade French scale median 8b, range 7b+ to 9a+) participated in the study. The control-group consisted of 20 male non-climbers (age 37y, 30–51y). The A2 and A4 pulleys in climbers were all significantly thicker (A2 Dig III 62%, Dig IV 69%; A4 Dig III 69%, Dig IV 76%) as compared to non-climbers pulleys. All PP's of the DIP joints were also significantly thicker, particularly at Dig III and IV (76 and 67%), whereas the PP's at PIP joints were only scarce significant for three joints. Differences of the diameter of the flexor tendons were less distinct (1–21%) being significant only over the middle phalanx. High load to the fingers of rock climbers after a minimum of 15 years of climbing years induced considerable connective tissue adaptions in the fingers, most distinct at the flexor tendon pulleys and joint capsule (PP) of the DIP joints and well detectable by ultrasound.
Williams, Sarah E; Guillot, Aymeric; Di Rienzo, Franck; Cumming, Jennifer
doi: 10.1080/17461391.2015.1051133pmid: 26313631
AbstractThe present study investigated the relationship between two of the most common measures of motor imagery ability, self-report ratings, and chronometric assessment. This was done for three types of imagery modalities: external visual imagery (EVI), internal visual imagery (IVI), and kinesthetic imagery (KI). Measures of imagery ability (i.e. self-report and mental chronometry) were also compared across skill levels. Participants (N = 198) completed the Movement Imagery Questionnaire-3 (MIQ-3) to generate self-report ratings. Chronometric assessment was obtained by recording the duration of each MIQ-3 movement imaged and physically performed and then calculating a discrepancy score. There were no significant correlations between self-report and mental chronometry for any of the three motor imagery types (p > .05). When assessing the different types of motor imagery ability using self-report ratings, elite athletes had significantly higher KI than IVI, which was in turn significantly higher than EVI (p < .05). When assessing motor imagery ability using mental chronometry, there were no significant differences in imagery type (p > .05). Findings suggest both measures address different components of MI quality and should be used together to obtain a more comprehensive assessment of motor imagery ability.
Hoon, Matthew W.; Fornusek, Ché; Chapman, Phillip G.; Johnson, Nathan A.
doi: 10.1080/17461391.2015.1053418pmid: 26681629
AbstractThis study examined the effect of dietary supplementation with inorganic nitrate ( ) on markers of contractile function in human knee extensors. In a double-blinded, randomized cross-over design, 18 (12 M) healthy participants undertook four days of supplementation with either nitrate-rich beetroot juice (NITRATE; days 1–3: 525 mg , day 4: 1050 mg ) or nitrate-depleted beetroot juice (PLACEBO). On the fourth day, isometric knee extension force was assessed during a series of voluntary and electrically evoked (stimulation) tests. In addition, muscular fatigue was examined in two separate continuous-stimulation (0.8 s tetanus with a 1:1 work:rest ratio for 102.4 s) fatigue tests, one with and one without blood flow restriction. There were no differences for maximum voluntary contraction, peak twitch force, half-relaxation time and the force–frequency relationship for stimulations up to 100 Hz between the NITRATE and PLACEBO trials. No differences between trials were observed in the non-restricted fatigue test, however NITRATE was found to attenuate the decline in force during the restricted test, such that the force at the 80 s mark (PLACEBO: 66 ± 11 vs. NITRATE 74 ± 9% of initial force; P = .01) and 102 s mark (PLACEBO: 47 ± 8% vs. NITRATE 55 ± 8%; P < .01) were significantly higher. These results suggest that four days of supplementation elicits peripheral responses in muscle that attenuate muscular fatigue during exhaustive exercise under hypovolemic conditions. This ergogenic action is likely attributable to improved Ca2+ handling in the muscle, or enhanced perfusion during ischemia.
Coratella, Giuseppe; Milanese, Chiara; Schena, Federico
doi: 10.1080/17461391.2015.1060264pmid: 26289478
AbstractAim of the study was to compare the effects of unilateral eccentric-only training using constant velocity vs. constant external load. Forty-seven participants were randomized in isokinetic (IK), dynamic constant external resistance (DCER) unilateral eccentric training or control groups. Knee extension 1RM and isometric, eccentric and concentric knee extensors peak torque, as well as changes in vastus lateralis fascicle pennation angle, fascicle length, muscle thickness, and quadriceps fat-free mass were measured. Both IK and DCER training consisted in 5 × 8 eccentric-only repetitions, 2d/w, for 6 weeks. IK and DCER training sessions were matched for total volume. After training, both IK and DCER similarly increased 1RM (respectively, +4.4 kg, CI95% 1.8–7.0 and +5.5 kg, CI95% 3.3–7.9), isometric (respectively, +34.5 N/m, CI95% 23.0–45.9 and +15.8, CI95% 5.4–26.2) and concentric peak torque (respectively, +17.0 N/m, CI95% 6.6 to +27.4 and 12.2 CI95% 2.8–21.7). IK increased eccentric peak torque significantly more than DCER (respectively, +84.2 N/m, CI95% 66.3–102.1 and +38.2 N/m, CI95% 21.9–54.4). Both IK and DCER similarly increased fascicle length (respectively, +14.7 mm, CI95% 5.4–24.0 and +14.4 mm, CI95% 5.4–23.3) and muscle thickness (respectively, +3.3 mm, CI95% 1.5–5.1, and +4.1 mm, CI95% 2.5–5.7). Matching the training volume resulted in similar adaptations comparing eccentric-only IK or DCER resistance training. Both in rehabilitation and in training practice, the use of easily available gym devices can be a good substitute for expensive and often unavailable IK devices.
Delextrat, Anne; Matthew, Dionne; Brisswalter, Jeanick
doi: 10.1080/17461391.2015.1061058pmid: 26289810
AbstractThe aim of this study was to investigate the effects of a weight loss intervention based on physical exercise on the relationship between energy cost and stride frequency during walking in obese teenagers. Participants aged 13–16 years old were assigned to a training (n = 14) and control (n = 10) groups. During eight weeks, the training group performed three 60-min weekly sessions of high-intensity intermittent activities coupled with aerobic training. Body composition, gait parameters and energy cost during 4-min walking bouts at participants’ most comfortable speed and preferred stride frequency (PSF), PSF-10%, PSF + 10%, PSF-20% and PSF + 20% were measured before and after intervention. The effects of training and stride frequencies on the energy cost of walking were analysed by an ANOVA with repeated measures. The main results showed that the exercise intervention induced a significant increase in walking speed (+23.2%), and significant decreases in body mass (−1.4%), body fat percentage (−2.1%) and energy cost of walking at various frequencies (decreases ranging from −10.5% to −20.4%, p < .05). In addition, significantly greater decreases were shown at high frequencies (p < .05). No significant differences were shown in the control group (p > .05). These results suggest that this type of training is beneficial to reduce walking energy cost of obese teenagers, in particular at high frequencies. This should improve their well-being during daily activities.
Martinent, Guillaume; Decret, Jean-Claude
doi: 10.1080/17461391.2015.1051131pmid: 26289726
AbstractYoung athletes in intensive training settings are confronted with a series of daily stressors although they have a smaller and less flexible coping repertoire than adults. Moreover, previous studies neglected the multivariate nature of coping. Therefore, the purpose of the current study was to first identify coping profiles of young athletes in response to daily stressors related to their competitive sport involvement. Second, the study examined: (a) if such profiles were similar across the three waves, (b) how many participants belonged to the same profile along the three waves, and (c) whether individuals from distinct profiles differed on burnout, stress, and recovery. One hundred and forty-seven young table-tennis players involved in intensive training settings completed the CICS, RESTQ-Sport, and ABQ three times during a 2-month period. Cluster analyses indicated three similar clusters across the three waves: task-oriented coping, distraction- and disengagement-oriented coping, and low coping profiles. The distribution of athletes significantly varied across waves. Burnout, stress, and recovery significantly differed across the coping profiles. Athletes from the task-oriented coping profile were characterized by the best psychological adjustment (high scores of recovery and low scores of stress and burnout). In contrast, athletes from the distraction- and disengagement-oriented coping profile were characterized by the worst psychological adjustment (high scores of stress and burnout and low scores of recovery). These findings highlighted that the coping profiles allow examining coping within a holistic approach, teasing out the complex associations with key outcomes, such as burnout, stress, and recovery.
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