SPORT EQUIPMENT - ENERGY AND PERFORMANCE

Over the past 30 years, sport scientists and sport equipment manufacturers have investigated ways of improving athletic equipment to enhance performance. The result is equipment that is stronger, lighter, more durable and more pleasant to use. Consequently, sport performances are faster, higher, longer and more accurate than they used to be. In fact every world record in sport which was set before 1980 has been broken an indication for the recent developments in athletic ability and improvements in athletic equipment

THE INFLUENCE OF GROUND CONTROL FOOTWEAR ON KNEE JOINT MOMENTS DURING RUNNING

Subjects who developed patellofemoral pain syndrome during running had higher internal knee abduction and external rotation moments than asymptomatic subjects (Stefanyshyn et al., in press). Footwear can significantly influence joint moments at the knee and ankle (Mündermann et al., 2003). Therefore, it was speculated that footwear could be developed specifically to reduce knee joint moments, primarily in the transverse and frontal planes. New prototypes were developed to allow the foot to displace both in a medial-lateral and anterior-posterior direction relative to the outsole. The purpose of this study was to determine if the prototype footwear allowing relative movement between the foot and outsole would reduce three-dimensional knee joint moments during running

Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location

Immediate Effects of Foot Orthoses Consistent Immediate Effects of Foot Orthoses on Comfort and Lower Extremity Kinematics, Kinetics, and Muscle Activity

In order to accommodate patients to new foot orthoses over time, two steps are required: The first is to obtain a baseline reading of the immediate effects across several weeks to ensure consistency. The second step is to look at changes with progressively longer wear periods similar to what occurs in general practice. This study addressed the first step. The purpose of this study was to determine whether the baseline reading of the immediate effects of foot orthoses on comfort and lower extremity kinematics, kinetics, and muscle activity is consistent between days. Participants were 21 recreational runners who volunteered for the study. Three orthotic conditions (posting, custom-molding, posting and custom-molding) were compared to a control (flat) insert. Lower extremity kinematic, kinetic, and EMG data were collected for 108 trials per participant and condition in 9 sessions for each person for running at 4 m/s. Comfort for all orthotic conditions was assessed in each session using a visual analog scale. Statistically significant session effects were detected using repeated-measures ANOVA (α = .05). Three of the 93 variables had a significant session effect. A significant interaction between orthotic condition and session was observed for 6 of the 93 variables. The results of this study showed that the effects of foot orthoses on comfort, lower extremity kinematics, kinetics, and muscle activity are consistent across a 3-week period when the wear time for each condition is restricted. Thus, foot orthoses lead to immediate changes in comfort, kinematics, kinetics, and muscle activity with limited use. These immediate effects of foot orthoses on comfort, kinematics, kinetics, and muscle activity are consistent between days

ATHLETE - EQUIPMENT INTERACTION

The purpose of this research is to understand how to match an athlete to a piece of athletic equipment. Individual athlete characteristics require specific equipment parameters to optimize performance. Similarly individual movement patterns can be matched to equipment characteristics to help prevent injury. The athlete and equipment form a biomechanical system influenced by biomechanical principles such as the force-length and force-velocity relationship of skeletal muscle. By understanding the athlete-equipment interaction, sport equipment can be tuned to individual athletes to maximize performance and minimize injury

Potential method of optimizing the klapskate hinge in speed skating

Etude des modifications biomécaniques à la hanche, au genou et à la cheville par le changement de position de la charnière du patin

Relationship between footwear comfort of shoe inserts and anthropometric and sensory factors

The purposes of this study were (a) to determine lower extremity anthropometric and sensory factors that are related to differences in comfort perception of shoe inserts with varying shape and material and (b) to investigate whether shoe inserts that improve comfort decrease injury frequency in a military population.; 206 military personnel volunteered for this study. The shoe inserts varied in arch and heel cup shape, hardness, and elasticity in the heel and forefoot regions. A no insert condition was included as the control condition. Measured subject characteristics included foot shape, foot and leg alignment, and tactile and vibration sensitivity of the plantar surface of the foot. Footwear comfort was assessed using a visual analog scale. Injury frequency was evaluated with a questionnaire. The statistical analyses included Student's t-tests for repeated measures, ANOVA (within subjects), MANOVA (within insert combinations), and chi-square tests.; The average comfort ratings for all shoe inserts were significantly higher than the average comfort rating for the control condition. The incidence of stress fractures and pain at different locations was reduced by 1.5-13.4% for the insert compared with the control group. Foot arch height, foot and leg alignment, and foot sensitivity were significantly related to differences in comfort ratings for the hard/soft, the viscous/elastic, and the high arch/low arch insert combinations.; Shoe inserts of different shape and material that are comfortable are able to decrease injury frequency. The results of this study showed that subject specific characteristics influence comfort perception of shoe inserts

Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.Peer Reviewe