Visual exploratory action – scanning movements expressed through left and right rotation of the head – allows perception of a surrounding environment and supports prospective actions. In the dynamically changing football environment, the extent to which exploratory action benefits a player’s subsequent performance with the ball is likely influenced by how and when the exploratory action occurs. Although few studies have examined the relationship between visual exploration and on-pitch football performance, it has been reported that a higher frequency of exploratory head movement up to 10-s before receiving the ball increases the likelihood of successful performance with the ball. This study investigated the relationship between head turn frequency and head turn excursion, and how and when exploratory head movement – within 10-s before ball possession – is related to performance with the ball in 11v11 match-play. Thirty-two semi-elite football players competed in 11v11 match-play. Head turn frequency and head turn excursion before ball possession were quantified with wearable inertial measurement units, and actions with the ball were coded via notational analysis. Odds ratio calculations were conducted to determine the associations between exploration variables and on-ball performance outcomes. A total of 783 actions with the ball were analyzed. Results revealed a strong relationship between head turn frequency and head turn excursion. Further, a higher than average head turn frequency and head turn excursion before receiving the ball resulted in a higher likelihood of turning with the ball, playing a pass in the attacking direction, and playing a pass to an area that is opposite to which it was received from. The strength of these outcomes varied for different time periods before receiving the ball. When players explored their environment with higher than average head turn frequency and excursion, they used more complex action opportunities afforded by the surrounding environment. Considerations for future research and practical implications are discussed.

Little is known about the actions supporting exploration and their relation to subsequent actions in situations when participants are surrounded by opportunities for action. Here, the movements that support visual exploration were related to performance in an enveloping football (soccer) passing task. Head movements of experienced football players were quantified with inertial measurement units. In a simulated football scenario, participants completed a receivingpassing task that required them to indicate pass direction to one of four surrounding targets, as quickly as they could after they gained simulated ball possession. The frequency of head movements before and after gaining ball possession and the pass response times were recorded. We controlled exploration time-the time before gaining simulated ball possession-to be 1, 2, or 3 seconds. Exploration time significantly influenced the frequency of head movements, and a higher frequency of head turns before gaining ball possession resulted in faster pass responses. Exploratory action influenced subsequent performatory action. That is, higher frequencies of head movements resulted in faster decisions. Implications for research and practice are discussed.

Weakley, J, Chalkley, D, Johnston, R, García-Ramos, A, Townshend, A, Dorrell, H, Pearson, M, Morrison, M, and Cole, M. Criterion validity, and interunit and between-day reliability of the FLEX for measuring barbell velocity during commonly used resistance training exercises. J Strength Cond Res 34(6): 1519–1524, 2020—The aim of this study was to assess the criterion validity, interunit reliability (accounting for technological and biological variance), and between-day reliability of a novel optic laser device (FLEX) for quantifying mean concentric velocity. To assess the validity against a three-dimensional motion capture system and interunit reliability with both technological and biological variation, 18 men and women completed repetitions at 20, 40, 60, 80, 90, and 100% of one repetition maximum in the free-weight barbell back squat and bench press. To assess interunit (technological only) reliability, a purpose-built, calibrated rig completed a set protocol with 2 devices. To assess between-day reliability of the technology, the same protocol was repeated 21 days later. Standardized bias, typical error of the estimate (TEE; %), and Pearson's correlation coefficient (r) were used to assess validity, whereas typical error and coefficient of variation (CV%) were calculated for reliability. Overall, TEE (±90 CL) between the FLEX and criterion measure was 0.03 (±0.004) and 0.04 (±0.005) m·s−1 in the back squat and bench press, respectively. For measures of reliability, overall interunit technological variance (CV% [± 90% confidence interval]) was 3.96% (3.83–4.12) but increased to 9.82% (9.31–10.41) and 9.83% (9.17–10.61) in the back squat and bench press, respectively, when biological variance was introduced. Finally, the overall between-day reliability was 3.77% (3.63–3.91). These findings demonstrate that the FLEX provides valid and reliable mean concentric velocity outputs across a range of velocities. Thus, practitioners can confidently implement this device for the monitoring and prescription of resistance training loads.

Warman, GE, Cole, MH, Johnston, RD, Chalkley, D, and Pepping, GJ. Using microtechnology to quantify torso angle during matchplay in field hockey.

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This study examined accuracy of ball flight predictions and error source for judging leg-before-wicket (LBW) in cricket using a video-based decision making task. Twenty-six club-elite umpires, 33 club-intermediate umpires, and 12 control participants viewed videos which depicted the typical view of an Umpire's perspective. Participants were asked to predict the final ball position at the stumps after the video was temporally occluded, using a computer cursor. Videos were occluded at two points, ball bounce and two frames post-bounce. Performance was measured using the horizontal and vertical error in pixels. The club-elite and club-intermediate umpires were more accurate than the control group. All groups made less horizontal error compared to vertical error, particularly in the post-bounce condition. Umpires were more certain of their decisions than control participants. The results indicate that umpires possess a domain-specific skill which enables them to more accurately predict ball path, a critical component of LBW judgements. The results also indicate that vertical judgements were poorer overall. This finding implies a specific potential training area for umpires.

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