Sarah M. Churchill

The effect of the bend on technique and performance during maximal effort sprinting.

This study investigated changes in performance and technique that occur during maximal effort bend sprinting compared with straight-line sprinting under typical outdoor track conditions. Utilising a repeated measures design, three-dimensional video analysis was conducted on seven male sprinters in both conditions (bend radius: 37.72 m). Mean race velocity decreased from 9.86 to 9.39 m/s for the left step (p = 0.008) and from 9.80 to 9.33 m/s for the right step (p = 0.004) on the bend compared with the straight, a 4.7% decrease for both steps. This was mainly due to a 0.11 Hz (p = 0.022) decrease in step frequency for the left step and a 0.10 m (p = 0.005) reduction in race step length for the right step. The left hip was 4.0° (p = 0.049) more adducted at touchdown on the bend than the straight. Furthermore, the bend elicited significant differences between left and right steps in a number of variables including ground contact time, touchdown distance and hip flexion/extension and abduction/adduction angles. The results indicate that the roles of the left and right steps may be functionally different during bend sprinting. This specificity should be considered when designing training programmes.

Physical, Psychological and Emotional Benefits of Green Physical Activity: An Ecological Dynamics Perspective

Increasing evidence supports the multiple benefits to physical, psychological and emotional wellbeing of green physical activity, a topic of increasing interest in the past decade. Research has revealed a synergistic benefit of green physical activity, which includes all aspects of exercise and physical activity in the presence of nature. Our theoretical analysis suggests there are three distinct levels of engagement in green physical activity, with each level reported to have a positive effect on human behaviours. However, the extent to which each level of green physical activity benefits health and wellbeing is assumed to differ, requiring confirmation in future research. This elucidation of understanding is needed because previous literature has tended to focus on recording empirical evidence rather than developing a sound theoretical framework to understand green physical activity effects. Here we propose an ecological dynamics rationale to explain how and why green physical activity might influence health and wellbeing of different population groups. This framework suggests a number of unexplored, interacting constraints related to types of environment and population groups, which shape reported levels of benefit of green physical activity. Further analysis is needed to clarify the explicit relationship between green physical activity and health and wellbeing, including levels of engagement, types of environmental constraints, levels of physical activity, adventure effects, skill effects and sampling of different populations.

Physical and emotional benefits of different exercise environments designed for treadmill running

(1) Background: Green physical activity promotes physical health and mental wellbeing and interesting questions concern effects of this information on designing indoor exercise environments. This study examined the physical and emotional effects of different nature-based environments designed for indoor treadmill running; (2) Methods: In a counterbalanced experimental design, 30 participants performed three, twenty-minute treadmill runs at a self-selected pace while viewing either a static nature image, a dynamic nature image or self-selected entertainment. Distance ran, heart rate (HR) and five pre-and post-exercise emotional states were measured; (3) Results: Participants ran farther, and with higher HRs, with self-selected entertainment compared to the two nature-based environment designs. Participants attained lowered anger, dejection, anxiety and increased excitement post exercise in all of the designed environments. Happiness increased during the two nature-based environment designs compared with self-selected entertainment; (4) Conclusions: Self-selected entertainment encouraged greater physical performances whereas running in nature-based exercise environments elicited greater happiness immediately after running.

Bend sprinting performance: new insights into the effect of running lane

Abstract Athletes in inner lanes may be disadvantaged during athletic sprint races containing a bend portion because of the tightness of the bend. We empirically investigated the veracity of modelled estimates of this disadvantage and the effect of running lane on selected kinematic variables. Three-dimensional video analysis was conducted on nine male athletes in lanes 8, 5 and 2 of the bend of an outdoor track (radii: 45.10, 41.41 and 37.72 m, respectively). There was over 2% (p < 0.05) reduction in mean race velocity from lane 8 (left step 9.56 ± 0.43 m/s, right step: 9.49 ± 0.41 m/s) to lane 5 (left step: 9.36 ± 0.51 m/s, right step: 9.30 ± 0.51 m/s), with only slight further reductions from lane 5 to lane 2 (left step: 9.34 ± 0.61 m/s, right step: 9.30 ± 0.63 m/s). Race velocity decreased mainly because of reductions in step frequency as radius decreased. These unique data demonstrate the extent of the disadvantage of inner lane allocation during competition may be greater than previously suspected. Variations in race velocity changes might indicate some athletes are better able to accommodate running at tighter radii than others, which should have implications for athletes’ training.

Measurement of bend sprinting kinematics with three-dimensional motion capture: a test–retest reliability study

ABSTRACT Sprint velocity decreases on the bend when compared with the straight, therefore understanding technique during bend sprinting could have important implications for aiding race performance. Few bend sprinting studies have used optoelectronic cameras to investigate kinematic variables. Limited published evidence regarding the reliability of marker sets in conditions representative of elite bend sprinting makes model selection difficult. Therefore, a test-retest protocol was conducted to establish the reliability and minimum detectable difference of a lower limb and trunk marker set during bend sprinting (radius: 36.5 m). Six participants completed five, 60 m trials at maximum effort, with data collected at 38–45 m. This was repeated 2–7 days later. Spatio-temporal (e.g., contact time) and kinematic variables (e.g., peak joint angles) were evaluated. Intra-class correlation coefficients (ICC) were used to determine the between- and within-day reliability. Between-day reliability (ICC 3, k) was fair to excellent for all variables. Compared to between-day, within-day reliability demonstrated stronger agreement for the majority of variables. Thus, same-day data collection is preferable. It has been established that the marker set is reliable for future use. In addition, the minimal detectable difference was calculated which serves as useful reference for future research in bend sprinting

Performance indicators that discriminate winning and losing in elite men’s and women’s Rugby Union

Abstract This study aimed to identify performance indicators that discriminate winning and losing in elite men’s and women’s Rugby Union during the latest World Cup competitions. The knockout stages of the men’s 2015 Rugby World Cup (n = 8) and women’s 2014 Rugby World Cup (n = 8) were compared. Findings suggest that in the men’s game, winning teams kicked a greater percentage of possession in the opposition 22–50 m with a view to gaining territory and pressuring the opposition (winners = 16%, losers = 7%). In the women’s game successful teams adopted a more possession-driven attacking approach in this area of the pitch. Successful women’s teams appear more willing to attack with ball in hand following a kick receipt and adopt a more expansive game through attacking with wider carries in the outside channels. The percentage of lineouts won on the opposition ball was found to be an important performance indicator that discriminates winners and losers, regardless of sex (winners = 18%, losers = 11%). Findings suggest successful men’s and women’s teams adopt different tactical approaches to knockout competitions, this knowledge should be used as a basis for coaches to develop tactical approaches and training methods which are sex dependent.

Effect of the ‘Crouch, Bind, Set’ engagement routine on scrum performance in English Premiership Rugby

The effect of the new scrum engagement sequence introduced at the start of the 2013/2014 season on scrum performance has not been evaluated. This study compared scrum performance indicators pre- (2012/2013 season) and post-law change (2013/2014). Several performance indicators at the scrum were identified in 20 games from each season of the English domestic Premiership. These included the number of penalties, free kicks and resets awarded. A Mann Whitney U test showed a significant increase in the number of scrums per game, from 17.50 to 23.85 (p = 0.003, ES = 0.47). This was contributed to by a 112% increase in the number of reset scrums (p < 0.0005). Of the resets, there was a significant increase in the number of scrums reset due to collapsing, which is of concern for player welfare. However, resets for collapsing accounted for a similar proportion of the total resets pre and post law change at 52% and 53%, respectively, and may be due to the relative novelty of the technique and stringent law enforcement increasing resets. In contrast, there was a decrease in the number of early engagements from 1.65 to 0.40 per match following the law change which is likely beneficial for player welfare.