Reliability and validity of different methods of estimating the one-repetition maximum during the free-weight prone bench pull exercise

ABSTRACT

This study examined the reliability and validity of three methods of estimating the one-repetition maximum (1RM) during the free-weight prone bench pull exercise. Twenty-six men (22 rowers and four weightlifters) performed an incremental loading test until reaching their 1RM, followed by a set of repetitions-to-failure. Eighteen participants were re-tested to conduct the reliability analysis. The 1RM was estimated through the lifts-to-failure equations proposed by Lombardi and O’Connor, general load-velocity (L-V) relationships proposed by Sánchez-Medina and Loturco and the individual L-V relationships modelled using four (multiple-point method) or only two loads (two-point method). The direct method provided the highest reliability (coefficient of variation [CV] = 2.45% and intraclass correlation coefficient [ICC] = 0.97), followed by the Lombardi’s equation (CV = 3.44% and ICC = 0.94), and no meaningful differences were observed between the remaining methods (CV range = 4.95–6.89% and ICC range = 0.81–0.91). The lifts-to-failure equations overestimated the 1RM (3.43–4.08%), the general L-V relationship proposed by Sánchez-Medina underestimated the 1RM (?3.77%), and no significant differences were observed for the remaining prediction methods (?0.40–0.86%). The individual L-V relationship could be recommended as the most accurate method for predicting the 1RM during the free-weight prone bench pull exercise.     

Bone mineral density and lean mass asymmetries are greater in cyclists than non-cyclists

ABSTRACT

Cyclists may be at greater risk of developing asymmetrical force and motion patterns than other ground-based athletes. However, functional asymmetries during cycling tend to be highly variable, making them difficult to assess. Dual-energy x-ray absorptiometry (DXA) measurements of areal bone mineral density (aBMD) and lean mass (LM) in the lower limbs may be a more sensitive and consistent method to identify asymmetries in cyclists. The goal of this study was to determine if competitive cyclists have greater levels of asymmetries in the lower body compared to non-cyclists using DXA. A secondary aim was to determine if aBMD and LM asymmetries change over the road cycling season. 17 competitive cyclists and 21 non-cyclist, healthy controls underwent DXA scans. Lower-body asymmetries were greater in cyclists compared to non-cyclists in aBMD and LM for all lower limb segments. However, these asymmetries did not tend to consistently favour a particular side, except for the pelvis having more LM on the dominant side. The were no longitudinal changes in aBMD or LM in the cyclists. Asymmetry analysis via DXA provides evidence that although functional asymmetries during cycling are variable, cyclists have increased lower body LM and aBMD asymmetries compared to non-cyclists.     

Balance and proprioception responses to FIFA 11+ in amateur futsal players: Short and long-term effects

ABSTRACT

Background: The FIFA 11+ has shown positive effects on balance and proprioception parameters in football players. As there have been very few research studies involving futsal, we examined the short and long term effects of the FIFA 11+ on static and dynamic balance, as well as proprioception in male amateur futsal players.

Methods: Seventy-one male futsal players were randomized to two groups (FIFA 11+: n = 37, age: 27.33 ± 4.33 years; Control: n = 34, age: 25.55 ± 4.65 years). Intervention lasted 10 weeks, 2 sessions per week, succeeded by a 10-week follow-up period. For balance testing, we assessed the single-legged postural sway with a force platform (static balance) and the Y balance test (dynamic balance). Proprioception was assessed with active joint position sense testing.

Results: Complete pre-post intervention and follow-up tests were available for 61 players. The FIFA 11+ group showed higher training exposure and lower body mass index and body weight. After adjustment for baseline differences, no significant differences between groups were observed in the pre-post changes for centre of pressure measures, Y-balance and proprioception parameters both at short and long-term.

Conclusions: Performing FIFA 11+ for 10 weeks did not improve static and dynamic balance as well as proprioception in amateur futsal players.     

Responsiveness of the anterior cruciate ligament – Return to Sports after Injury (ACL-RSI) and Injury – Psychological Readiness to Return to Sport (I-PRRS) scales

ABSTRACT

The ACL-Return to Sport after Injury (ACL-RSI) and Injury-Psychological Readiness to Return to Sport (I-PRRS) scales were developed to assess psychological factors associated with return to sports. Validity and reliability have been determined. The aim of this study was to investigate the responsiveness of the Dutch ACL-RSI and I-PRRS. Seventy patients with ACL reconstruction completed both scales twice 2 months apart, plus a Global Rating of Change (GRC) questionnaire. Distribution and logistic regression-based methods were used to study responsiveness. The Standardized Response Mean (SRM) for the ACL-RSI was 0.3 and for the I-PRRS 0.1, indicating low responsiveness. The minimally important change (MIC) for ACL-RSI was 2.6 and for the I-PRRS 0.9. Since the standard error of measurement (SEM) and smallest detectable change (SDC) were larger than MIC in individual patients, it does not seem possible to distinguish minimally important changes from measurement error in individual patients with either scale. At the group level responsiveness seemed sufficient; hence, both scales can be used to investigate the effectiveness of an intervention at the group level. Both scales can also be used in cross-sectional research and in clinical practice as screening instruments to identify patients at risk of not returning to sports.     

Does self-determined motivation interact with environmental contexts to influence moderate-to-vigorous physical activity during a girls’ youth sport camp?

ABSTRACT

Objective: To explore whether basketball player’s self-determined motivation interacts with environmental contexts and coach training to influence percentage time in moderate-to-vigorous physical activity (%MVPA). Methods: A secondary analysis of data from 76 girls (mean ± SD, 10.5 ± 1.0 years) was conducted. Players were classified as high self-determined motivation (HSDM) or low self-determined motivation (LSDM) and randomised to trained (intervention) or untrained (control) coaches. Training included 2 workshops on strategies for activity-promoting practices. Girls were exposed to environmental contexts (practices and games) led by a trained/untrained coach (depending on arm) and one without coaches (free time) daily. Girls wore accelerometers each day. Using mixed random-effects models, the influence of motivation, context and training on %MVPA was analysed. Results: Trained coaches’ practices were associated with the greatest %MVPA with no difference between HSDM and LSDM players (38.28 ± 1.77%; 37.64 ± 1.80%; p = 0.66). HSDM players had significantly greater %MVPA versus LSDM players during untrained coaches’ practices (23.58 ± 1.77%; 20.51 ± 1.78%; p = 0.03). During games with trained coaches, HSDM players had greater %MVPA compared to LSDM players (23.79 ± 1.76%; 18.56 ± 1.74%; p < 0.001). No between-group difference in %MVPA during free time was found (12.85 ± 0.82%; 13.39 ± 0.84%; p = 0.64). Conclusion: The impact of individual differences in self-determined motivation on %MVPA during practices was attenuated when coaches were trained to implement activity-promoting practices.     

Changing attitudes and intentions related to doping: An analysis of individual differences in need for cognition

ABSTRACT

Research has shown that athletes’ attitudes towards the use of banned performance-enhancing substances are reliable predictors of their intentions to use these substances, which in turn can be relevant predictors of their actual doping behaviours. Despite the important role played by attitudes and intentions in doping, research analysing how to change those attitudes and intentions is relatively scarce. The present study examined how individual differences in Need for Cognition (NC, Cacioppo & Petty, 1982) influenced doping-related attitude change and subsequent behavioural intentions. Participants were randomly assigned to read a persuasive message either against or in favour of legalising the use of several banned substances, including anabolic androgenic steroids (AAS) and Erythropoietin (EPO). In addition, participants completed the NC scale, and finally reported their attitudes and behavioural intentions regarding the legalisation proposal. As hypothesised, results showed that participants who received an anti-legalisation message had significantly more unfavourable attitudes towards the proposal than participants who received a pro-legalisation message, regardless of NC. However, as predicted, NC moderated the relationship between individuals’ attitudes and their intentions. That is, high-NC participants showed greater attitude-intention correspondence than low-NC participants.     

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome

Abstract

The primary objective of this study was to examine the relationship between heart rate intensity and pedometer step counts in adolescents. To determine cardiorespiratory fitness, 106 participants (47 boys, 59 girls, mean age 14.2 years, s = 0.8) completed the Queen's College Step Test and were classified as having low, moderate or high cardiorespiratory fitness. Adolescents also completed a 10-min treadmill trial while wearing a pedometer and heart rate monitor. The participants were instructed to maintain their heart rate between 65 and 75% of their maximum heart rate while running or walking on a treadmill. A heart rate of 65–75% maximum was associated with 146 steps per minute (s = 22) in boys and 137 steps per minute (s = 22) in girls. Results of analysis of variance indicated that there was a main effect for level of fitness (F _2,102 = 9.36, P < 0.001). The correlation between mean steps per minute and estimated maximum oxygen consumption was statistically significant (r = 0.44, P < 0.001). The results from this study suggest that a step rate of 130 steps per minute is equal to 65–75% maximum heart rate in low-fit adolescents and achieving 130 steps per minute could be used as an initial goal to improve fitness.     

An investigation of a novel three-dimensional activity monitor to predict free-living energy expenditure

Abstract

The aim of this study was to assess the capability of the 3dNX? accelerometer to predict energy expenditure in two separate, free-living cohorts. Twenty-three adolescents and 14 young adults took a single dose of doubly labelled water and wore a 3dNX? activity monitor during waking hours for a 10-day period while carrying out their normal routines. Multiple linear regression with backward elimination was used to establish the strength of the associations between various indices of energy expenditure, physical activity counts, and anthropometric variables. 3dNX? output accounted for 27% and 35% of the variance in the total energy expenditure of the adolescent and young adult cohort, respectively. The explained variance increased to 78%, with a standard error of estimate of 7%, when 3dNX? output was combined with body composition variables. The 3dNX? accelerometer can be used to predict free-living daily energy expenditure with a standard error of estimate of 1.65 MJ in adolescents and 1.52 MJ in young adults. The inclusion of anthropometric variables reduces the error to approximately 1 MJ. Although it remains to cross-validate these models in other populations, early indications suggest that the 3dNX? provides a useful method of predicting energy expenditure in free-living individuals.     

Causal attribution and emotion in the days following competition

Abstract

We examined the extent to which attributions are consistent in the days following competition and how attributions made immediately after competition may influence the temporal patterning of emotions experienced in response to competition. A sample of 60 adult female golfers completed measures of performance satisfaction, causal attribution, and emotion immediately after competition, 5 h after competition, and 2 days after competition. Repeated-measures multivariate analysis of covariance indicated that attributions did not change over this period. Emotions showed a significant decrease in intensity over the 5-h post-competition period. Regression analyses indicated that changes in anger and dejection were more likely in the case of less successful performances. For anger, attributions moderated this level of change. Golfers experienced anger for a longer period when they identified the cause of poor performance as stable rather than unstable. Thus, in the present sample although attributions did not change over 2 days, the longevity of anger depended on the attributions made immediately after competition.