Purpose: Several studies have investigated whether shoe cushioning properties have an effect on running economy. However, the findings have not been unanimous. Studies have shown both increases and decreases in running economy with soft shoes, while other studies have shown participant specific differences. Therefore, the purpose of this study was to add to the body of knowledge describing the effects of shoe cushioning properties on running economy. Methods: This study was comprised of two experiments; one using a stationary metabolic analysis system to measure oxygen consumption during treadmill running, and one using a portable metabolic analysis system to measure oxygen consumption during over-ground running. Twelve aerobically fit athletes participated in each experiment. Two professionally constructed pairs of prototype running shoes were provided by adidas AG for this experiment (Soft shoe and Control shoe). The shoes were identical in construction with the only differences being the midsole material and corresponding stiffness and energy return. Results: For both the treadmill and over-ground experiments, the Soft shoe condition was associated with statistically significantly decreased oxygen consumption compared to the Control shoe condition (Treadmill p = 0.044, Over-ground p = 0.028). In the treadmill experiment, 10 of the 12 subjects consumed less oxygen while wearing the more compliant/resilient condition, with an average decrease for all subjects of 1.0%. In the over-ground experiment 9 of the 12 subjects consumed less oxygen while running in the more compliant/resilient condition, with an average decrease for all subjects of 1.2%. Conclusion: Running shoes with softer and more resilient midsoles were found to influence running economy by 1.0% on average during treadmill and over-ground experiments.

Authors who report ground reaction force (GRF), free moment (FM), and resultant joint moments usually normalize these variables by division normalization. Normalization parameters include body weight (BW), body weight x height (BWH), and body weight x leg length (BWL). The purpose of this study was to explore the appropriateness of division normalization, power curve normalization, and offset normalization on peak GRF, FM, and resultant joint moments. Kinematic and kinetic data were collected on 98 subjects who walked at 1.2 and 1.8 m/s and ran at 3.4 and 4.0 m/s. Linear curves were best fit to the data, and regression analyses performed to test the significance of the correlations. It was found that the relationship between peak force and BW, as well as joint moments and BW, BWH, and BWL, were not always linear. After division normalization, significant correlations were still found. Power curve and offset normalization, however, were effective at normalizing all variables; therefore, when attempting to normalize GRF and joint moments, perhaps nonlinear or offset methods should be implemented.

Prior research has shown that footwear can enhance athletic performance. However, public information is not available on what basketball shoe properties should be selected to maximise movement performance. Therefore, the purpose of the study was to investigate the influence of basketball shoe mass, outsole traction, and forefoot bending stiffness on sprinting, jumping, and cutting performance. Each of these three basketball shoe properties was systematically varied by ±20% to produce three shoe conditions of varying mass, three conditions of varying traction, and three conditions of varying bending stiffness. Each shoe was tested by 20 recreational basketball players completing maximal effort sprints, vertical jumps, and a cutting drill. Outsole traction had the largest influence on performance, as the participants performed significantly worse in all tests when traction was decreased by 20% (p < 0.001), and performed significantly better in the cutting drill when traction was increased by 20% (p = 0.005). Forefoot bending stiffness had a moderate effect on sprint and cutting performance (p = 0.013 and p = 0.016 respectively) and shoe mass was found to have no effect on performance. Therefore, choosing a shoe with relatively high outsole traction and forefoot bending stiffness should be prioritised, and less concern should be focused on selecting the lightest shoe.

Forefoot bending stiffness is a footwear property that has recently been gaining interest despite previously receiving limited attention compared to other footwear characteristics. This review focuses on relevant research studies examining the influence of forefoot bending stiffness on reducing injury and optimizing performance. Discussion of the current limitations and need for future research within the realm of forefoot bending stiffness is also highlighted. By reducing the amount of metatarsophalangeal extension, increased bending stiffness could not only reduce injury risk (e.g. turf-toe), but also serve as a treatment for metatarsal stress fractures by offloading the metatarsals. However, there are surprisingly limited in-depth studies examining how altered forefoot bending stiffness influences injury. Many unknown factors still need to be studied including the appropriate magnitude of bending stiffness and the influence that altering forefoot bending stiffness may have on the injury risk of other joints such as the ankle and knee. Forefoot bending stiffness can influence performance; however, the exact mechanism remains unclear. Early studies focused on foot energetics, while recent studies have shown the importance of altering the movement of the centre of pressure under the foot and the gearing ratio at the ankle joint. There appears to be a specific amount of forefoot bending stiffness for optimal performance. Future research should focus on identifying the exact mechanism of performance improvement with modified bending stiffness to help determine how this optimal stiffness can be identified.

Background: Traction is influenced by the sole architecture and playing surface, with increases in traction potentially leading to injury. The mechanism as to how or why increased traction could lead to injury remains unknown. Purpose: This study was undertaken to determine how shoes of different sole designs and traction influence knee and ankle joint moments. Study Design: Controlled laboratory study. Methods: Traction testing was performed on 2 shoes of varying sole designs (tread vs smooth) using a robotic testing machine. All testing was conducted on a 60-cm × 90-cm piece of sample track surface. Kinematic and kinetic data were then collected on 13 recreational athletes performing running V-cuts in the 2 different shoe conditions. Five trials per condition were collected with reflective markers placed on the right shank and shoe of each participant. Kinematic and kinetic data were collected using an 8–high-speed camera system and force plate. Results: The coefficient of translational traction and the peak moment of rotation were both significantly higher in the tread shoe compared with the smooth shoe (1.00 vs 0.87 and 23.87 N·m vs 16.12 N·m, respectively). The high-traction shoe had significantly higher peak ankle external rotation moments (89.58 N·m vs 80.17 N·m), peak knee external rotation moments (36.23 N·m vs 32.02 N·m), peak knee adduction moments (224.0 N·m vs 186.8 N·m), and knee adduction angular impulse (2.10 Nms vs 1.83 Nms) compared with the low-traction shoe. Conclusion: Increased shoe traction significantly increased ankle and knee joint moments during a V-cut. Despite the significant difference in traction, no difference in performance was observed. These changes could have an effect on ankle and knee joint injury. Clinical Relevance: Shoes with decreased traction could be used in sports to reduce the joint moments in the knee and ankle and potentially reduce injury without a loss in performance.