Shoe collar height and heel counter-stiffness for shoe cushioning and joint stability in landing

ABSTRACT

This study examined the effects of shoe collar-height and counter-stiffness on ground reaction force (GRF), ankle and knee mechanics in landing. Eighteen university basketball players performed drop landing when wearing shoes in different collar height (high vs. low) and counter-stiffness (stiffer vs. less stiff). Biomechanical variables were measured with force platform and motion capturing systems. Two-way repeated measures ANOVA was performed with α = 0.05. Wearing high collar shoes exhibited smaller peak ankle dorsiflexion and total sagittal RoM, peak knee extension moment, but larger peak knee varus moment than the low collar shoes. Stiffer counter-stiffness shoes related to smaller ankle inversion at touchdown and total coronal RoM, but larger peak knee flexion and increased total ankle and knee sagittal RoM than the less stiff counter-stiffness. Furthermore, wearing stiffer counter-stiffness shoes increased forefoot GRF peak at high collar condition, while no significant differences between counter-stiffness at low collar condition. These results suggest that although higher collar height and/or stiffness heel counter used can reduce ankle motion in coronal plane, it would increase the motion and loading at knee joint, which is susceptible to knee injuries. These findings could be insightful for training and footwear development in basketball.     

Flexible and inexpensive: Improving learning transfer and program evaluation through participant action plans

Action plans have been shown to improve transfer of learning and have proven an effective tool in training evaluation. This study describes how action planning was simply and successfully adapted to a preexisting curriculum with few additional resources. The decision to use participant action planning, the administration of it, and the participants' and the sponsor's responses are discussed, along with suggestions for future human performance technology research.     

The effects of imagery training on fast isometric knee extensor torque development

We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90 ° knee angle but were tested also at 120 °. At 90 ° knee angle, maximal torque increased (-8%) similarly in all three training groups. The torque-time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P < 0.05) after physical training (by -100%), but only at 90 °. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r (2) = 0.81, P < 0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.     

The BASES expert statement on emotion regulation in sport

Emotions experienced before and during sports competition have been found to influence sports performance. Emotion regulation is defined as the automatic or deliberate use of strategies to initiate, maintain, modify or display emotions (Gross & Thompson, 2007) and is proposed to occur when a discrepancy exists between current and desired emotions. Two distinct motivations to regulate emotion - hedonic and instrumental (in short, for pleasure or for purpose) - have been proposed (Tamir, 2009). The instrumental approach might provide a more fruitful area of investigation for sports researchers as some athletes hold beliefs that supposedly pleasant emotions such as happiness and calmness associate with poor performance and supposedly unpleasant emotions such as anxiety and anger associate with good performance (Hanin, 2010). Athletes are more likely to try to regulate an emotion if they believe that doing so will facilitate performance. Strategies that encourage re-appraisal of factors that trigger emotions are proposed to be preferable. In this British Association of Sport and Exercise Sciences (BASES) expert statement, a summary of the key theoretical issues are offered leading to evidence-based recommendations for practitioners and researchers.