Physiological Responses to Maximal Treadmill and Handweighted Exercise

Abstract

The purpose of this investigation was to compare the peak physiological responses among four protocols that employed different amounts of handweighted exercise in 16 males (aged 26.3 ± 4.1 years). The four protocols were (a) uphill treadmill running (UR; 3.36 m-s¹, 2.5% grade increase-3 min¹); (b) uphill treadmill walking while pumping 1.36kg handweights (HW) (UWHW; 1.79ms¹, 5.0% grade increase-3 min¹; (c) treadmill walking while pumping .91-kg HW (WHW; 1.79 m-s¹, 0% grade, .91kg HW increase-3 min¹); and (d) standing in place and pumping HW (SHW; arm work as described in WHW). It was hypothesized that the peak responses would be inversely proportional to the estimated muscle mass activated (i.e., UR = UWHW > WHW > SHW). Dependent variables included peak oxygen uptake (VO₂ peak), peak heart rate (HRpeak), peak ventilation (V_epeak), and peak respiratory exchange ratio (RERpeak). No differences were noted between UR and UWHW with respect to any of the dependent variables. All variables (except RERpeak) were greater (p < .01) in UR and UWHW than either WHW or SHW. RERpeak was greater (p < .01) in UR and UWHW than in WHW. VO₂peak and HRpeak were greater (p < .01) in WHW when compared to SHW. Mean VO₂peak was 97.5, 69.7, and 60% of UR for UWHW, WHW, and SHW, respectively. Therefore, walking and pumping handweights provides a maximal stimulus to the oxygen transport system.     

Dress for fit: An exploration of female activewear consumption

While the female activewear market is growing rapidly, research on activewear consumption and female consumers is lagging. Existing researchers have failed to produce an in-depth understanding of female consumers’ perceptions of activewear, thereby providing limited insights for the activewear industry. Drawing upon brand association theory and the functional, expressive, and aesthetic model, the authors identify important attributes of activewear brands and how attributes lead to benefits pursued by female activewear consumers. Focus groups were conducted with 72 female activewear consumers in Australia. Findings reveal three product-related attributes (functional design, colour, and size and fit) and two non-product-related attributes (price and model imagery) influence the fulfillment of four benefits (mood enhancement, exercise facilitation, healthy and active lifestyle, and physical fit body image). This research contributes theoretical and empirical knowledge about activewear consumption and the vertical structure of brand associations. Findings of this research can help activewear brands deliver benefits to female consumers through improved product designs and marketing strategies.     

Trust: the power that binds in team supervision of doctoral students

Team supervision of doctoral students adds new dimensions and complexities to relationships within the teams that impact functionality of the team. Trust emerged as a significant theme in recent qualitative research into the quality of team supervision of doctoral students. Trust was cited as a key component in successful team collaborations, and the missing component in dysfunctional teams. Definitions refer to trust as the belief of truthfulness, reliability or faith in another person’s abilities. My hypothesis is that trust operates as a form of power in team supervision. It is a form of power that enables voice, resilience and creativity in teams. This article concludes that placing trust in others in supervisory teams is a deliberate decision by candidates and supervisors. It is a decision to engage in a team context despite known risks and may be understood as a gamble on the reliability of others in the expectation of reciprocity. By conceptualising trust as a form of power, strategies that engender and maintain trust may be utilised more intentionally.     

The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.