Confounding compression: the effects of posture,sizing and garment type on measured interface pressure in sports compression clothing

The purpose of this investigation was to measure the interface pressure exerted by lower body sports compression garments, in order to assess the effect of garment type, size and posture in athletes. Twelve national-level boxers were fitted with sports compression garments (tights and leggings), each in three different sizes (undersized, recommended size and oversized). Interface pressure was assessed across six landmarks on the lower limb (ranging from medial malleolus to upper thigh) as athletes assumed sitting, standing and supine postures. Sports compression leggings exerted a significantly higher mean pressure than sports compression tights (P < 0.001). Oversized tights applied significantly less pressure than manufacturer-recommended size or undersized tights (P < 0.001), yet no significant differences were apparent between different-sized leggings. Standing posture resulted in significantly higher mean pressure application than a seated posture for both tights and leggings (P < 0.001 and P = 0.002, respectively). Pressure was different across landmarks, with analyses revealing a pressure profile that was neither strictly graduated nor progressive in nature. The pressure applied by sports compression garments is significantly affected by garment type, size and posture assumed by the wearer.     

An analysis of the value of multiple mentors in formalised elite coach mentoring programmes

Background: Within the context of sports coaching and coach education, formalised mentoring relationships are often depicted as a mentor–mentee dyad. Thus, mentoring within sports coaching is typically conceptualised as a one-dimensional relationship, where the mentor is seen as the powerful member of the dyad, with greater age and/or experience [Colley, H. (2003). Mentoring for Social Inclusion. London: Routledge].

Aim: The aim of this study was to explore the concept of a multiple mentor system in an attempt to advance our theoretical and empirical understanding of sports coach mentoring. In doing so, this paper builds upon the suggestion of Jones, Harris, and Miles [(2009). “Mentoring in Sports Coaching: A Review of the Literature.” Physical Education and Sport Pedagogy 14 (3): 267–284] who highlight the importance of generating empirical research to explore current mentoring approaches in sport, which in turn can inform meaningful formal coach education enhancement. The significance of this work therefore lies in opening up both a practical and a theoretical space for dialogue within sports coach education in order to challenge the traditional dyadic conceptualisation of mentoring and move towards an understanding of ‘mentoring in practice’.

Method: Drawing upon Kram’s [(1985). Mentoring at Work: Developmental Relationships in Organisational Life. Glenview, IL: Scott Foresman] foundational mentoring theory to underpin a multiple mentoring support system, 15 elite coach mentors across a range of sports were interviewed in an attempt to explore their mentoring experiences. Subsequently, an inductive thematic analysis endeavoured to further investigate the realities and practicalities of employing a multiple mentoring system in the context of elite coach development.

Results: The participants advocated support for the utilisation of a multiple mentor system to address some of the inherent problems and complexities within elite sports coaching mentoring. Specifically, the results suggested that mentees sourced different mentors for specific knowledge acquisition, skills and attributes. For example, within a multiple mentor approach, mentors recommended that mentees use a variety of mentors, including cross-sports and non-sport mentors.

Conclusion: Tentative recommendations for the future employment of a multiple mentoring framework were considered, with particular reference to cross-sports or non-sport mentoring experiences.     

Quiet eye training aids the long-term learning of throwing and catching in children: Preliminary evidence for a predictive control strategy

Abstract

Quiet eye training (QET) may be a more effective method for teaching children to catch than traditional training (TT) methods, but it is unclear if the benefits accrued persist in the long term. Thirty children were randomly allocated into a QET or TT group and, while wearing a mobile eye tracker, underwent baseline testing, training and two retention tests over a period of eight weeks, using a validated throw and catch task. During training, movement-related information was provided to both groups, while the QET group received additional instruction to increase the duration of their targeting fixation (QE1) on the wall prior to the throw, and pursuit tracking (QE2) period on the ball prior to catching. In both immediate (R1) and delayed (R2, six weeks later) retention tests, the QET group had a significantly longer QE1 duration and an earlier and longer QE2 duration, compared to the TT group, who revealed no improvements. A performance advantage was also found for the QET compared to the TT group at both R1 and R2, revealing the relatively robust nature of the visuomotor alterations. Regression analyses suggested that only the duration of QE1 predicted variance in catch success post-training, pointing to the importance of a pre-programming visuomotor strategy for successful throw and catch performance.     

A prospective examination of the impact of high levels of exercise training on sedentary behaviour

The aim of this study is to determine changes in sedentary behaviour in response to extensive aerobic exercise training. Participants included adults who self-selected to run a marathon. Sedentary behaviour, total activity counts and physical activity (PA) intensity were assessed (Actigraph GT3X) for seven consecutive days during seven assessment periods (?3, ?2, and ?1 month prior to the marathon, within 2 weeks of the marathon, and +1, +2, and +3 months after the marathon). Models were fitted with multiple imputation data using the STATA mi module. Random intercept generalized least squares (GLS) regression models were used to determine change in sedentary behaviour with seven waves of repeated measures. Results: Twenty-three individuals (mean?±?S_x: 34.4?±?2.1y, 23.0?±?1.9% fat, 15 women, 8 men) completed the study. Marathon finishing times ranged from 185 to 344 minutes (253.2?±?9.6 minutes). Total counts in the vertical axis were 1,729,414 lower one month after the race, compared with two months prior to the race (peak training). Furthermore, counts per minute decreased by 252.7 counts·minute^?1 during that same time period. Daily sedentary behaviour did not change over the seven assessment periods, after accounting for age, gender, per cent body fat, wear time, marathon finishing time, and previous marathon experience. This prospective study supports the notion that PA and sedentary behaviours are distinct, showing that sedentary behaviour was not impacted by high levels of aerobic training.     

Maximal heart rate declines linearly with age independent of cardiorespiratory fitness levels

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HR_max) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HR_max with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HR_max for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R² (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HR_max explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HR_max.     

Exercise but not metformin improves health-related quality of life and mood states in older adults with type 2 diabetes

The aim of this cohort study is to analyse the effect of three types of treatment: (i) exercise training with multicomponent exercise (E); (ii) pharmacologic treatment with oral hypoglycaemic drug – metformin (M); and (iii) a combined therapy – exercise and metformin (E?+?M) on health-related quality of life (HRQoL) and mood states in older adults with type 2 diabetes (T2D) with comorbidity in an early stage of the disease. Participants (n?=?284) underwent 1 of the following 3 conditions: (i) E (n?=?59) trained three times/week; (ii) M (n?=?30) used 850?mg of metformin twice daily; and (iii) E?+?M (n?=?195) combined exercise and metformin. Furthermore, participants completed baseline and 2-year follow-up evaluations including a Shortform Health Survey 36, Profile of Mood States – Short-form, the health history questionnaires, anthropometric, and blood biochemistry. E and E?+?M revealed improved mood states, with large effect size on the vigour domain, and moderate effect size in the anger and total mood disturbance (TMD) domains (P?<?0.05), in comparison with the M group. After 24 months’ intervention, the E and E?+?M groups perceived better physical and mental HRQoL than the M group. The M group unchanged HRQoL domains (P?>?0.05). Metformin had no significant effect on the self-referred HRQoL in T2D participants aged above 60 years, in an early stage of the disease. The E and E?+?M were the most effective long-term therapies to improve mood states and HRQoL in older adults with T2D.     

The effects of localised fatigue on upper extremity jump shot kinematics and kinetics in team handball

Team handball is a popular sport worldwide that requires numerous throws to be made throughout the course of a game. Because of the upper extremity demands of repetitive throwing, it is possible that fatigue can alter the mechanics of a shot. The purpose of this study was to determine the influence of localised fatigue on jump shot kinematics and kinetics. Eleven male team handball players (23.1 ± 3.1 years; 185.1 ± 8.3 cm; 89.7 ± 12.2 kg) volunteered. An electromagnetic tracking system was used to examine the jump shot prior to and following localised fatigue. The fatiguing protocol consisted of throwing a 2.2 kg medicine ball into a rebounder until volitional fatigue. No significant kinematic or kinetic differences were observed following fatigue. Shoulder external rotation was ?74.8 ± 14.9° prior to and ?79.0 ± 14.7° following fatigue at MER. Scapula, external rotation at ball release (BR) prior to fatigue was ?2.2 ± 7.0° and ?3.2 ± 11.1° following fatigue. Scapular internal rotation, at maximum shoulder internal rotation (MIR), changed from 18.4 ± 11.2° to 20.4 ± 11.8°. Ball velocity decreased from19.8 m · s^–1 to 18.8 m · s^–1 (P = 0.12). Accuracy percentage in the pre-fatigue trials was 60.8 ± 14.1% and 52.8 ± 12.7% following fatigue (P = 0.20). While no significant changes were observed, it is possible that other fatiguing protocols that more closely represent the aerobic and throwing demands of the sport may have a greater effect on the kinematics and kinetics of the jump shot.     

Fluid balance and hydration assessment during the weight-stable preparation phase in elite youth boxers

This study investigated (i) the prevalence of hypohydration and (ii) association between urinary indices of hydration status and confounding factors (e.g., urine protein content, water intake) in elite youth boxers during their weight-stable phase before competition. Sixteen national champion boxers (all male, 17 ± 1 y) were measured on 3 occasions (baseline, day 3, day 10), 30-day prior to competition. Body mass, total body water, urine specific gravity (USG), osmolality (UOSM) and total protein content (TPC) were evaluated to determine hydration status and fluid balance. Overall macronutrient and water intake were assessed using dietary records. Both UOSM and USG increased from day 3 to day 10 by 16% and 0.4% (P < 0.001), despite athletes being in their weight-stability period, and regardless of ad libitum fluid intake. Hypohydration was universally prevalent among all athletes on both test days with USG: 1.027 ± 0.003 g · mL^?1 and UOSM: 1035 ± 108 mOsmol · kg^?1. An inverse association between mean UOSM values and mean water intake was observed (R = ?0.52, P = 0.04), while TPC was not associated with any urinary dehydration markers (USG, P = 0.51; UOSM, P = 0.61). The present outcomes find that the most prevalent urinary dehydration markers used to classify hydration status in competition exhibit large variability, even during weight-stable periods.