Relationship between maximal oxygen uptake and oxygen uptake attained during treadmill middle-distance running

Traditionally, it has been assumed that during middle-distance running oxygen uptake (VO2) reaches its maximal value (VO2max) providing the event is of a sufficient duration; however, this assumption is largely based on observations in individuals with a relatively low VO2max. The aim of this study was to determine whether VO2max is related to the VO2 attained (i.e. VO2peak) during middle-distance running on a treadmill. Fifteen well-trained male runners (age 23.3 +/- 3.8 years, height 1.80 +/- 0.10 m, body mass 76.9 +/- 10.6 kg) volunteered to participate in the study. The participants undertook two 800-m trials to examine the reproducibility of the VO2 response. These two trials, together with a progressive test to determine VO2max, were completed in a randomized order. Oxygen uptake was determined throughout each test using 15-s Douglas bag collections. Following the application of a 30-s rolling average, the highest VO2 during the progressive test (i.e. VO2max) was compared with the highest VO2 during the 800-m trials (i.e. VO2peak) to examine the relationship between VO2max and the VO2 attained in the 800-m trials. For the 15 runners, VO2max was 58.9 +/- 7.1 ml x kg(-1) x min(-1). Two groups were formed using a median split based on VO2max. For the high and low VO2max groups, VO2max was 65.7 +/- 3.0 and 52.4 +/- 1.8 ml x kg(-1) x min(-1) respectively. The limits of agreement (95%) for test-retest reproducibility for the VO2 attained during the 800-m trials were +/- 3.5 ml x kg(-1) x min(-1) for a VO2peak of 50.6 ml x kg(-1) x min(-1) (the mean VO2peak for the low VO2max group) and +/- 2.3 ml x kg(-1) x min(-1) for a VO2peak of 59.0 ml x kg(-1) x min(-1) (the mean VO2peak for the high VO2max group), with a bias in VO2peak between the 800-m runs (i.e. the mean difference) of 1.2 ml x kg(-1) x min(-1). The VO2peak for the 800-m runs was 54.8 +/- 4.9 ml x kg(-1) x min(-1) for all 15 runners. For the high and low VO2max groups, VO2peak was 59.0 +/- 3.3 ml x kg(-1) x min(-1) (i.e. 90% VO2max) and 50.6 +/- 2.0 ml x kg(-1) x min(-1) (i.e. 97% VO2max) respectively. The negative relationship (-0.77) between VO2max and % VO2max attained for all 15 runners was significant (P = 0.001). These results demonstrate that (i) reproducibility is good and (ii) that VO2max is related to the %VO2max achieved, with participants with a higher VO2max achieving a lower %VO2max in an 800-m trial on a treadmill.     

Skiing‐Skating

An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three‐dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure‐related injuries.     

Early Head Start Relationships: Association with Program Outcomes

Research Findings: Interpersonal relationships among staff caregivers, parents, and children have been recommended as essential aspects of early childhood intervention. This study explored the associations of these relationships with program outcomes for children and parents in 3 Early Head Start programs. A total of 71 children (8–35 months, M = 20), their parents, and 33 program caregivers participated. The results showed that caregiver–child relationships were moderately positive, secure, and interactive and improved in quality over 6 months, whereas caregiver–parent relationships were generally positive and temporally stable. Caregiver–child relationships were more positive for girls, younger children, and those in home-visiting programs. Caregiver–parent relationships were more positive when parents had higher education levels and when staff had more years of experience, had more positive work environments, or had attained a Child Development Associate credential or associate's level of education rather than a 4-year academic degree. Hierarchical linear modeling analysis suggested that the quality of the caregiver–parent relationship was a stronger predictor of both child and parent outcomes than was the quality of the caregiver–child relationship. There were also moderation effects: Stronger associations of caregiver–parent relationships with observed positive parenting were seen in parents with lower education levels and when program caregivers had higher levels of education. Practice or Policy: The results support the importance of caregiver–family relationships in early intervention programs and suggest that staff need to be prepared to build relationships with children and families in individualized ways. Limitations of this study and implications for program improvements and future research are discussed.     

Thinking about the same things differently: Examining perceptions of a non-profit community sport organisation

This paper explores the differing perceptions and identity responses (identification, apathy and disidentification) that potentially exist in relation to one non-profit Community Sport Organisation (CSO), and whether they explain variations in individuals’ existing values and beliefs, sport interest, community identification and views about one organisation's legitimacy. Data were collected using a quantitative online survey (n = 390), then analysed using Confirmatory Factor Analysis (CFA) and Multiple Analysis of Variance (MANOVA) to test three hypotheses investigating whether existing values and beliefs, shared community values, local players, organisational practices and sport interest varied based on perception of organisational image and identity response. Based on the contributions of this study, non-profit CSOs should spend time developing understanding of the key dimensions that make them relevant to constituents and to decipher the values and beliefs that underpin what external audiences expect from organisations. In addition, understanding specifically what a CSO's audience expects is fundamental if the organisation is to be perceived as legitimate in relation to its purpose.     

Understanding the role of shaft stiffness in the golf swing

Theoretically, shaft stiffness can alter shot distance by increasing clubhead speed or altering clubhead orientation at impact. A 3D forward dynamics model of a golfer and flexible club simulated the downswing. A genetic algorithm optimized the coordination of the model’s muscles (four torque generators) to maximize clubhead speed. The maximum torque output and maximum rate of torque development from the torque generators were varied to simulate the swing of golfers that generate different clubhead speeds. Four shafts of varying stiffness (flexible, regular, stiff, and completely rigid) were entered into these simulations to examine the role that shaft flexibility had on clubhead speed and orientation at impact. Shaft stiffness was found to have a meaningful effect only on clubhead orientation (dynamic loft and dynamic close) at impact. There was no evidence to support the premise that matching the stiffness properties of the shaft with the golfer would improve clubhead speed.