In this study, criteria are used to identify whether a subject has elicited maximal oxygen uptake. We evaluated the validity of traditional maximal oxygen uptake criteria and propose a novel set of criteria. Twenty athletes completed a maximal oxygen uptake test, consisting of an incremental phase and a subsequent supramaximal phase to exhaustion (verification phase). Traditional and novel maximal oxygen uptake criteria were evaluated. Novel criteria were: oxygen uptake plateau defined as the difference between modelled and actual maximal oxygen uptake >50% of the regression slope of the individual oxygen uptake–workrate relationship; as in the first criterion, but for maximal verification oxygen uptake; and a difference of ≤4 beats·min –1 between maximal heart rate values in the 2 phases. Satisfying the traditional oxygen uptake plateau criterion was largely an artefact of the between-subject variation in the oxygen uptake–workrate relationship. Secondary criteria, supposedly an indicator of maximal effort, were often satisfied long before volitional exhaustion, even at intensities as low as 61% maximal oxygen uptake. No significant mean differences were observed between the incremental and verification phases for oxygen uptake (t = 0.4; p = 0.7) or heart rate (t = 0.8; p = 0.5). The novel oxygen uptake plateau criterion, maximal oxygen uptake verification criterion, and maximal heart rate verification criterion were satisfied by 17, 18, and 18 subjects, respectively. The small individual absolute differences in oxygen uptake between incremental and verification phases observed in most subjects provided additional confidence that maximal oxygen uptake was elicited. Current maximal oxygen uptake criteria were not valid and novel criteria should be further explored.
Introduction: Pacing can be defined as an ability to distribute available energy resources during the race (Hettinga et al. , 2006). It’s a determinant of athletic performance, affected by an interaction between previous experience, performance feedback and individual risk-traits (Micklewright et al. , 2014). Selective processing of internal physiological and external feedback information is a complex process that informs pace decision-making (Renfree et al. , 2014), but little is known about how athletes seek-out and interpret information to make pacing decisions. This study compared information-seeking behavior between novice and experienced cyclists. Methods : Novice (n=10) and experienced (n=10) cyclists performed two 16.09 km self-paced time-trials (TT’s), one week apart. Time-trials were performed on a Velotron cycle ergometer using a video simulated course. Performance information (power, speed, cadence, distance and time), heart rate and the 6-20 RPE scale were displayed in front of participants during TT’s. A head-mounted eye-tracker was used to measure the frequency and duration of gazes towards each type of information. Gaze was coded as ‘other’ when participants were not looking at any of the information specified above. Cumulative gaze duration for each information source was calculated as a percentage of TT completion time. Between and within-subjects ANOVA’s were used to compare performance, fixation times and fixation frequencies between groups and trials. Results : Performance between TT’s did not change for experts (27:55±1:21 vs. 27:42±1:30 mins:secs) or novices (30:53±3:14 vs. 30:16±2:56 mins:secs). Cycling speed in each segment was faster among experts compared to novices, but both groups maintained an even pace through the TT’s. In TT1, experts primarily looked at speed (30.1%) followed by other (19.3%) then distance (18.3%). Novices were less selective during TT1, looking at distance (21.6%), video (15.3%), other (14.3%), and power (13.4%) (Fig 1A). Experts looked at speed more in TT2 (Speed 33.4%, Distance 17.7%, and other 16%) and novices looked at the video less (Distance 23.1%, Speed 14.4%, Power 13.8%, Other 13.6% and Video 10.5%) (Fig1B). Differences in fixation time were found between groups for primary (P=0.003) and secondary sources of information (P=0.043) (Fig 2A). Differences were also found in frequency for primary (P=0.003) and secondary source of information (P=0.04) respectively (Fig. 2B) . Discussion: Experts were found to look at speed as their primary source of information compared to novices who looked at distance. This may indicate a preference for performance related decision-making in experts compared to a focus on task completion among novices.
The primary aim of computer-assisted knee arthroplasty is to improve the alignment of the implanted prostheses. Accurate component alignment is dependent on the establishment of accurate anatomical reference points. Current techniques for establishing the center of the ankle joint, especially in the coronal plane, rely solely on clinical judgment in relation to the position of the center of the ankle joint. The aim of this study was to determine if an algorithm could be developed, based on establishing the most prominent points on the medial and lateral malleoli on 3D CT scans, to accurately and reproducibly establish the position of the center of the ankle joint. To determine this, images of 20 ankles were obtained and axial, coronal, and sagittal 2D reconstructions were manipulated on a workstation. Two observers independently performed relevant measurements and calculations. The calculated data was found to be reproducible with a very small standard deviation in each plane. This algorithm is able to provide accurate measurements of the ankle joint in knee navigation surgery. Caution must be exercised in anatomically abnormal ankles, as the calculations of the ankle center were found to be significantly different.
The psychological construct of affect is proposed to significantly contribute to pacing decisions during exercise. Borg's RPE scale, another important regulator of work rate, is criticized as an inadequate measure of the multiple perceptual responses experienced. This study aimed to examine power output distribution and associated changes in affect, self-efficacy, perceptual cues, HR, and respiratory gases during both 16.1- and 40-km self-paced cycling time trials (TT). Secondly, the differentiation between physical perceptions of exertion and sense of effort in self-paced exercise was investigated.Fifteen trained male cyclists completed 16.1- and 40-km TT using a CompuTrainer cycle ergometer. Time, power output distribution, affect, self-efficacy, physical RPE (P-RPE), task effort and awareness (TEA), HR, and respiratory gases were measured throughout each TT. Linear mixed models explored associations of these variables with power output distribution and the relationship between P-RPE and TEA.Similar pacing strategies were adopted in the 16.1- and 40-km TT (P = 0.31), and the main effects were found for affect (P = 0.001) and RER (P < 0.001). Interactions between affect (P = 0.037) and RER (P = 0.004), with condition, indicated closer associations with power output distribution in 16.1 km than that in 40 km TT. P-RPE was not significantly different from TEA (P = 0.053).A significant association between affect and power output distribution suggests that affective responses are task dependent even in self-paced exercise, and a greater association is demonstrated in higher intensity, 16.1 km TT. Furthermore, physical perceptions of exertion are not clearly differentiated from the sense of effort in self-paced exercise.
Abstract Background Stroboscopic visual training (SVT) has been shown to improve cognitive skills and perceptual performance by carrying out events under situations of intermittent vision. Aims The aim of this study was to investigate whether an SVT training period could improve the eye–hand coordination (EHC) performance on a practiced task for a group of sports participants. Methods Sixty-two male participants were randomly assigned to either a strobe group (SG n = 31), or control group (CG n = 31). The method employed a Sport Vision Trainer™ 80 sensor pad to measure the mean speed of reaction time of participants extinguishing randomly illuminated lights on an electronic board. One trial consists of 20 lights. One week following pre-testing on the Sport Vision Trainer™ (4 × 6 trials), a pre-training baseline assessment of 1 × 6 trials was conducted to measure their abilities to complete the EHC task. Four × six trials (480 lights) were then completed in the training phase with the CG continuing to train with unimpaired vision, whilst the SG wore Nike Vapor Strobe ® (controlled rate of 100 ms visible to 150 ms opaque). Post-training assessments were administered immediately, 10 min and 10 days after SVT each consisting of six trials (120 lights). A visual search (VS) non-trained transfer test was also administered pre-SVT and after 10 days. This involved an e-prime programme using a laptop where participants had to identify a target stimulus located amongst distractor stimuli. Results Treatment effects were observed at each time point. Baseline performance was significantly related to retention performance immediately ( p = .003), 10-min post ( p = .001) and 10 days post-training ( p = .002). No significant differences were found for the VS test. Conclusion An acute SVT exposure using stroboscopic goggles significantly improved EHC performance. Future research should explore these mechanisms further using different exposure, frequencies, and focused identification of training drills as a complementary intervention for individual or team sports.
Laboratory based cycling time trials (TT) are widely used by both researchers and practitioners, as a method of assessing cycling performance in a controlled environment. Assessments of performance often use TT durations or distances between 20 min and one hour and in the UK the 10 mile (16.1 km) TT is the most frequently used race distance for trained cyclists. The 16.1 km TT has received relatively minimal, but increased attention as a performance criterion in the literature. Therefore, the aim of this study was to assess the reliability of 16.1 km TT performance in a large cohort of trained cyclists using the CompuTrainer cycling ergometer. Trained male cyclists (n = 58, mean±SD age 35±7 yr, height 179±6 cm, weight 79.1±9.4 kg, VO2max. 56.6±6.6 ml.kg.min-1, PPO 365±37 W) performed an initial incremental exercise test to determine PPO and VO2max. The participants then performed two 16.1 km TT on a CompuTrainer cycle ergometer separated by 3-7 days. Differences in time, power output and speed were determined using a Wilcoxon signed ranks or paired t-tests. Reproducibility of the TT performance measures was performed using the coefficient of variation (CV), intraclass correlations, and typical error (TE). There were no differences between any of the performance criteria for the whole cohort (Mean difference = 0.06 min, 0.09 km.h-1, 1.5 W, for time, mean speed and power respectively) between TT1 and TT2. All TT performance data were very reproducible (CV range = 1.1-2.7%) and demonstrated trivial or small TE. The slower cyclists demonstrated marginally lower reliability (CV range = 1.3-3.2%) compared to the fastest group (CV range = 0.7-2.0%). The 16.1 km TT on the CompuTrainer represents a very reliable performance criterion for trained cyclists. Interpretation of test-retest performance outcomes should be performed in the context of the TE of each performance indicator.
This study examined the utility of Maddux’s (1993) revised theory of planned behavior toward the prediction of exercise intentions and adherence. A prospective design was employed whereby 120 private sector health club members completed self report measures pertaining to various components of the revised theory. Adherence was measured prospectively over a sixteen week period by monitoring attendance toward prescribed exercise programs. Path analysis was used to analyze the predictions of the revised theory. Goodness of fit indices suggested an acceptable fit with the data (RMSEA 0.94; SRMSR <0.08). However, self-efficacy was the only theoretical construct to predict intention, with the latter being the only determinant of exercise adherence. Contrary to the revised theory hypotheses, the remaining contribution of the social cognitive variables in predicting exercise intentions and adherence were minimal. The results of the present investigation provide equivocal support for the revised theory; however future research may wish to consider several of the methodological issues discussed.
Abstract The purpose of this study was to investigate recreational participants' experiences of adhering to a sport injury rehabilitation program. Six participants undertaking a rehabilitation program for a tendonitis‐related injury as a result of sport involvement took part in this study. Data were collected using semi‐structured interviews and were thematically analyzed using interpretative phenomenological analysis (Smith & Osborn, 2003). Five themes emerging from the data set were motivation, confidence, coping, social support, and pain. Specifically, a lack of motivation and confidence were perceived to have a negative effect upon home‐based rehabilitation adherence while ineffective coping strategies, over support and pain, appeared to have an adverse influence on rehabilitation adherence in a clinic setting. The use of effective coping strategies and varied types of social support aided rehabilitation adherence. Applied implications and future research directions are discussed
The provision of performance-related feedback during exercise is acknowledged as an influential external cue used to inform pacing decisions. The provision of this feedback in a challenging or deceptive context allows research to explore how feedback can be used to improve performance and influence perceptual responses. However, the effects of deception on both acute and residual responses have yet to be explored, despite potential application for performance enhancement. Therefore, this study investigated the effects of challenging and deceptive feedback on perceptual responses and performance in self-paced cycling time trials (TT) and explored whether changes in performance are sustained in a subsequent TT following the disclosure of the deception. Seventeen trained male cyclists were assigned to either an accurate or deceptive feedback group and performed four 16.1 km cycling TTs; (1 and 2) ride-alone baseline TTs where a fastest baseline (FBL) performance was identified, (3) a TT against a virtual avatar representing 102% of their FBL performance (PACER), and (4) a subsequent ride-alone TT (SUB). The deception group, however, were initially informed that the avatar accurately represented their FBL, but prior to SUB were correctly informed of the nature of the avatar. Affect, self-efficacy and RPE were measured every quartile. Both groups performed PACER faster than FBL and SUB (p < 0.05) and experienced lower affect (p = 0.016), lower self-efficacy (p = 0.011), and higher RPE (p < 0.001) in PACER than FBL. No significant differences were found between FBL and SUB for any variable. The presence of the pacer rather than the manipulation of performance beliefs acutely facilitates TT performance and perceptual responses. Revealing that athletes' performance beliefs were falsely negative due to deceptive feedback provision has no effect on subsequent perceptions or performance. A single experiential exposure may not be sufficient to produce meaningful changes in the performance beliefs of trained individuals beyond the acute setting.
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