Darla R. Smith

Running in new and worn shoes: a comparison of three types of cushioning footwear

Objectives: In this study, the effect of shoe degradation on running biomechanics by comparing the kinetics and kinematics of running in new and worn shoes was investigated. Three types of footwear using different cushioning technologies were compared. Design: Longitudinal study. Setting: Pre- and post-tests on overground running at 4.5 m s−1 on a 20-m laboratory runway; performance measured using a force platform and a motion capture system. Participants: 24 runners (14 men and 10 women) Interventions: 200 miles of road running in the same pair of shoes. Within-group factor: shoe condition (new/worn); between-group factor: footwear type (air/gel/spring). Main outcome measurements: Stance time was calculated from force data. External loads were measured by maximum vertical force and loading rate. Kinematic changes were indicated by sagittal plane angles of the torso, hip, knee and ankle at critical events during the stance phase. Results: Stance time increased (p = 0.035) in worn shoes. The torso displayed less maximum forward lean (p<0.001) and less forward lean at toe-off (p<0.001), while the ankle displayed reduced maximum dorsiflexion (p = 0.013) and increased plantar flexion at toe-off (p<0.001) in worn shoes. No changes in the hip and knee angles. No between-group difference among the three footwear groups or condition by type interaction was found in any measured variables. Conclusions: As shoe cushioning capability decreases, runners modify their patterns to maintain constant external loads. The adaptation strategies to shoe degradation were unaffected by different cushioning technologies, suggesting runners should choose shoes for reasons other than cushioning technology.

Integrating Physical Education, Math, and Physics

T he primary goal of education is to help students gain the knowledge and skills necessary to solve the problems that will occur in life. One of the most touted methods for doing this is curriculum integration (McBee, 2000). The concept of integrated curricula has been around since the 19th century, and it is once again at the forefront of educational change (Vars, 1991). Those who are leading this movement claim that an integrated curriculum is far superior to one that is compartmentalized and discipline-based (Venville, Wallace, Rennie, & Malone, 2000). Among the leaders of the movement are educational psychologists who claim that an integrated curriculum, by design, reaches more students by

Soccer: A comparison of knee joint laxity among male and female collegiate soccer players and non‐athletes

Abstract Female athletes are at least twice as likely to sustain an anterior cruciate ligament injury than male athletes. The underlying cause of ACL injury is multifactorial. However, several researchers have identified knee joint laxity as a possible contributing factor. The purpose of this study was to provide a comparison of knee joint laxity between male and female collegiate soccer players and male and female non‐athletes. Thirty‐nine (19 male, 20 female) apparently healthy, collegiate athletes from the University of Texas at El Pasos 2001‐2002 womens intercollegiate soccer team and mens club soccer team, and forty (20 male, 20 female) non‐athletic students volunteered to participate. All participants were tested bilaterally using the KT‐1000 MEDmetric knee joint ligament arthrometer. Three tests were used to determine anterior laxity: passive displacement, active displacement, and the Lachman test. The mean passive displacement, mean active displacement, and Lachman (only for the left leg) were significantly lower for the athletic group than for the non‐athletic group. There were no significant differences found between males and females for the passive and active drawer tests. However, females had significantly more laxity than males in the Lachman test. These findings suggest that strength and conditioning may play a more significant role in knee joint laxity than the sex of the individual.Female athletes are at least twice as likely to sustain an anterior cruciate ligament injury than male athletes. The underlying cause of ACL injury is multifactorial. However, several researchers have identified knee joint laxity as a possible contributing factor. The purpose of this study was to provide a comparison of knee joint laxity between male and female collegiate soccer players and male and female non-athletes. Thirty-nine (19 male, 20 female) apparently healthy, collegiate athletes from the University of Texas at El Pasos 2001-2002 womens intercollegiate soccer team and mens club soccer team, and forty (20 male, 20 female) non-athletic students volunteered to participate. All participants were tested bilaterally using the KT-1000 MEDmetric knee joint ligament arthrometer. Three tests were used to determine anterior laxity: passive displacement, active displacement, and the Lachman test. The mean passive displacement, mean active displacement, and Lachman (only for the left leg) were significantly lower for the athletic group than for the non-athletic group. There were no significant differences found between males and females for the passive and active drawer tests. However, females had significantly more laxity than males in the Lachman test. These findings suggest that strength and conditioning may play a more significant role in knee joint laxity than the sex of the individual.

Determination of Human Gait Phase Using Fuzzy Inference

This paper discusses the design and implementation of a fuzzy inference system for the recognition of human gait phases. In particular, this work focuses on using the angles of the joints of lower limb to determine the current stage of a subjects gait cycle. The fuzzy rule-based system was developed using typical joint angle trajectories over a single gait cycle. The behavior of each joint was examined to determine appropriate rules for differentiating between gait phases. The completed system was then tested using joint angle trajectories measured from healthy human test subjects and shown to be capable of reproducing the gait phase transitions found by a human expert.

Preventing Running Injuries through Barefoot Activity.

JOPERD • Volume 79 No. 4 • April 2008 R unning has become immensely popular in the United States, with an estimated 28.8 million participants annually (National Sporting Goods Association, 2007), even though there are high reports of running injuries. Common theories have pointed to impact forces and overpronation as the main contributors to chronic running injuries. However, even with the use of increased cushioning and orthotics, the incidence of running injuries remains high. For instance, over a period of six months, it was found that 79 percent of runners sustained a running-related injury (Lun, Meeuwisse, Stergiou, & Stefanyshyn, 2004). The high incidence of running injuries has caused some researchers to evaluate other strategies that may reduce injury occurrence. One method involves internal adaptations. This method uses barefoot activity to promote positive adaptations to running stresses, which may increase the strength of supportive structures, thereby reducing running injury rates (Kurz & Stergiou, 2003; Robbins & Hanna, 1986). The purpose of this article is to describe for coaches and runners the theory behind the use of barefoot activity as a method of reducing running injuries. It will also provide practical advice for implementing barefoot activity in a training regimen.

Correlation of three different knee joint position sense measures

OBJECTIVE The purpose of this study was to investigate correlation during concurrent measurement among three knee joint position sense (JPS) measures in sitting position and between two measures in standing position. METHODS Isokinetic dynamometer, electrogoniometer, and two dimensional (2D) video analysis were used for measuring knee JPS. The JPS was measured both in sitting and standing positions. All three measures were employed concurrently to measure knee JPS in sitting position; however, only the electrogoniometer and 2D video analysis were concurrently used in the standing position. The knee JPS was recorded in sitting position at 15 degrees, 30 degrees, and 45 degrees and in standing at high, mid and low knee flexion positions. RESULTS The results of the study suggest excellent correlation (0.94-0.98) between the electrogoniometer and 2D video analysis measures in standing position. In sitting position, good to excellent correlation (0.63-0.92) was found between the isokinetic dynamometer and electrogoniometer; however, fair to good correlation was found between 2D video analysis and either of the two measures (electrogoniometer [0.52-0.57] and isokinetic dynamometer [0.41-0.63]. CONCLUSION Either 2D video or an electrogoniometer may be used to measure JPS in standing position; however, in sitting position 2D video should not be used if the camera is required to be placed at 10 degrees from the plane of motion.

Comparison of Lower Body Specific Resistance Training on the Hamstring to Quadriceps Strength Ratios in Men and Women

In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional and functional H:Q ratios were calculated. Hamstring strength improved similarly in men and women, but improvement in quadriceps strength was significantly greater in men, while women showed only modest improvements. For the conventional and functional H:Q ratios, women showed significantly greater improvements than men. Both men and women were able to exceed the commonly recommended 0.6 conventional and 1.0 functional H:Q ratios after the 12-week lower-body resistance training program.

Comparison of longitudinal biomechanical adaptation to shoe degradation between the dominant and non-dominant legs during running

This study compared the biomechanical adaptation to running shoe degradation between the dominant (D) and non-dominant (ND) leg. Twenty-four runners performed a pre-test in the laboratory, completed 200 miles of road running in a pair of assigned shoes and then returned for a post-test. Kinetic and kinematic data of running in new and worn shoes were collected. Repeated measures ANOVA (Shoe×Leg) were used to analyze temporal, kinetic and kinematic variables (α=.05). A symmetry index (SI) was calculated for the temporal and kinetic variables and paired t-tests were used to compare the SI between shoe conditions. Stance time increased by approximately 7 ms in worn shoes (p=.027). Bilateral differences in the kinematic change (Shoe×Leg interaction) were seen in the torso (p<.05), knee (p<.05), marginally at the hip (p<.10) but not the ankle. No difference in kinetic variables or SI was observed. When running in worn shoes, the torso displayed reduced forward lean for both sides and to a greater extent during the D leg strike. The D hip and knee showed a more extended position for the worn shoe condition while an increased flexion was observed in the ND leg. Most of the kinematic differences observed were small and within the intra-subject variability measured during the same session. Future studies may consider performing a three-dimensional analysis at a higher sample rate and further explore whether asymmetrical adaptation is related to running injuries.

AN ANALYSIS OF A DISCRETE COMPLEX SKILL USING BERNSTEIN'S STAGES OF LEARNING '

The purpose of this study was to provide quantitative data about changes in coordination after practicing a racquetball forehand drive serve. Novice women (N= 10) were videotaped before and after 10 min. of practicing a racquetball forehand drive serve on Day 1, and after 10-min. practice sessions on consecutive Days 2 through 5. The PEAK5 Morion Measurement System was used to evaluate the following dependent variables: (a) range of motion of the wrist, elbow, upper torso, and pelvis from backswing to ball contact; (b) racket head velocity at ball contact; and (c) coordination. Coordination was evaluated based on analysis of the angular velocity graphs of each performance to assess sequencing and timing of the segmental contributions. Shared positive contribution was assessed between adjacent 2-segment combinations: pelvis-torso and elbow-wrist. A repeated-measures analysis of variance indicated racket velocity, pelvic rotation, and upper torso rotation significantly increased over the 5 days of practice. Although participants increased their pelvic and torso ranges of motion and racket velocity, improvement in coordination was not documented.

Exercise and Sport Science

Whether your interest is in teaching, coaching, fitness, or management, the Department of Exercise and Sport Science is committed to helping each student achieve his or her maximum potential. Each student is assigned a faculty adviser to assist with academic and career decisions. Our highly acclaimed “learn by doing” reputation is further enhanced by providing students with hands-on educational experiences in their area of choice. While maintaining a strong tradition in activities and the sciences, the department also emphasizes innovative programs and activities designed to maintain healthy, active life styles.