The use of a running power-meter for performance analysis in five-a-side football.

BACKGROUND: Power output considers all movement aspects of the game of football and could have meaningful impact for teams. PURPOSE & METHODS: To assess inter-reliability of ten power meters designed for running; and as a descriptor of individual and team performance during a five-a-side football match. The work aimed to assess inter-device reliability of running power-meters combined with data analysis from intermittent running, along with descriptives of player work rate, gait and team performance during a small-sided game of football. METHODS: 10 different running power meters inter-reliability were on a treadmill at 8, 10, 12, and 16 km h-1 for 60 s in a random order. Football players (N = 10) performed the Yo-Yo ET1 with the running power meters to determine participants' endurance capability, while assessing the ability to record metrics of gait and power output during intermittent running. Following a period of 7-days participants took part in a 20 min small-sided game of football wearing the running power meters to provide descriptors of work and gait. RESULTS: Good inter-device reliability for the power meters (CV 1.67, range 1.51-1.94 %) during continuous treadmill running were found. Overall mean ± SD results for Yo-Yo ET1 power output 263 ± 36W, power:weight 3.59 ± 0.34W∙kg-1 significantly (p < 0.05) increased with successive stages, while ground-contact time 234 ± 17 ms, and vertical oscillation 90.7 ± 27 mm did not change (p > 0.05). Descriptive analysis of the small-sided game presented mean ± SD absolute and relative power outputs of 148 ± 44W and 1.98 ± 0.53W∙kg-1, equating to 54 ± 21 %Wmax and 74 ± 5%HRmax. Characteristics of gait included cadence 125 ± 22 rpm, ground contact time 266 ± 19 ms, and vertical oscillation 76.7 ± 7 mm. The winning team worked relatively harder than the losing team (53.3 ± 0.7 %Wmax vs 46.7 ± 0.4 %Wmax, p < 0.0001) with more time (398 s vs 141 s) spent above 70 %Wmax. SIGNIFICANCE: As such, the use of a running power-meter is a useful tool for comparing work rate and aspects of gait between team members while more research is required to investigate relative work rate (%Wmax) within the field.

Economic investment by ant colonies in searches for better homes.

Organisms should invest more in gathering information when the pay-off from finding a profitable resource is likely to be greater. Here, we ask whether animal societies put more effort in scouting for a new nest when their current one is of low quality. We measured the scouting behaviour of Temnothorax albipennis ant colonies when they inhabit nest-sites with different combinations of desirable attributes. We show that the average probability of an ant scouting decreases significantly with an increase in the quality of the nest in which the colony currently resides. This means that the greater the potential gain from finding a new nest, the more effort a colony puts into gathering information regarding new nest-sites. Our results show, for the first time to our knowledge, the ability of animal societies to respond collectively to the quality of a resource they currently have at their disposal (e.g. current nest-site) and regulate appropriately their information gathering efforts for finding an alternative (e.g. a potentially better nest-site).