This study examined the mechanics of translation and rotation during the conventional and handspring soccer throw-ins. Thirteen male collegiate soccer players were filmed at 100 fps while performing a conventional soccer throw-in for distance. Additionally, two male collegiate and two male youth league soccer players were filmed at 200 fps while performing a handspring throw-in. Analysis of the conventional throw-in revealed that rapid trunk flexion, and shoulder and elbow extension just prior to release appear to make important contributions to the performance variables (initial ball velocity, angle of release, range, angular momentum). Results of the handspring throw-in analysis suggest that the angular momentum generated during the preparatory and ball support phases was transferred to the arms, forearms, and ball during the latter stages of the movement. Although generalization to a larger population is limited, the results of this study suggest that the handspring throw-in technique has the potential to generate greater release velocities and longer throws, thereby enhancing scoring opportunities during throw-in situations.
Stephen P. Messier and Mary Ann Brody
C. Mark Woodard, Margaret K. James and Stephen P. Messier
Our purpose was to compare methods of calculating loading rate to the first peak vertical ground reaction force during walking and provide a rationale for the selection of a loading rate algorithm in the analysis of gait in clinical and research environments. Using vertical ground reaction force data collected from 15 older adults with symptomatic knee osteoarthritis and 15 healthy controls, we: (a) calculated loading rate as the first peak vertical force divided by the time from touchdown until the first peak; (b) calculated loading rate as the slope of the least squares regression line using vertical force and time as the dependent and independent variables, respectively; (c) calculated loading rate over discrete intervals using the Central Difference method; and (d) calculated loading rate using vertical force and lime data representing 20% and 90% of the first peak vertical force. The largest loading rate, which may be of greatest clinical importance, occurred when loading rates were calculated using the fewest number of data points. The Central Difference method appeared to maximize our ability to detect differences between healthy and pathologic cohorts. Finally, there was a strong correlation between methods, suggesting that all four methods are acceptable. However, if maximizing the chances of detecting differences between groups is of primary importance, the Central Difference method appears superior.
Stephen P. Messier, Christopher D. Thompson and Walter H. Ettinger Jr.
The purpose of this study was to determine the long-term effects of aerobic walking and weight training interventions on gait mechanics and knee pain in older adults with knee osteoarthritis (OA). One hundred three older adults (age ≥60 years) with radio-graphic evidence of knee OA were randomized to one of three treatment groups: aerobic walking, health education control, or weight training. Both exercise intervention groups exercised 3 days · week-1 for 18 months. The aerobic group significantly improved temporal components of gait as well as knee and ankle joint kinematics relative to the health education group across the 18-month intervention. Moreover, the weight training group exhibited significantly greater ankle plantar flexion velocity. Analysis of the ground reaction forces indicated that the aerobic group exhibited significantly greater force relative to the health education group. Finally, both exercise groups exhibited significantly less knee pain than the health education group. The results suggest that long-term aerobic walking and, to a lesser extent, weight training regimens improve walking mechanics in older adults with knee osteoarthritis. These improvements in gait are associated with a reduction in knee pain during activities of daily living.
Elizabeth Chmelo, Barbara Nicklas, Cralen Davis, Gary D. Miller, Claudine Legault and Stephen Messier
To assess correlates of physical activity, and to examine the relationship between physical activity and physical functioning, in 160 older (66 ± 6 years old), overweight/obese (mean body mass index = 33.5 ± 3.8 kg/m2), sedentary (less than 30 mins of activity, 3 days a week) individuals with knee osteoarthritis.
Physical activity was measured with accelerometers and by self-report. Physical function was assessed by 6-min walk distance, knee strength, and the Short Physical Performance Battery. Pain and perceived function were measured by questionnaires. Pearson correlations and general linear models were used to analyze the relationships.
The mean number of steps taken per day was 6209 and the average PAEE was 237 ± 124 kcal/day. Participants engaged in 131 ± 39 minutes of light physical activity (LPA) and 10.6 ± 8.9 minutes of moderate-vigorous physical activity (MPA/VPA). Total steps/day, PAEE, and minutes of MPA/VPA were all negatively correlated with age. The 6-min walk distance and lower extremity function were better in those who had higher total steps/day, higher PAEE, higher minutes of MPA/VPA, and a higher PASE score.
This study demonstrates that a population who has higher levels of spontaneous activity have better overall physical function than those who engage in less activity.
Stephen P. Messier, Walter H. Ettinger Jr, Thomas E. Doyle, Timothy Morgan, Margaret K. James, Mary L. O'Toole and Robert Burns
The purpose of our study was to examine the association between obesity and gait mechanics in older adults with knee osteoarthritis (OA). Subjects were 101 older adults (25 males and 76 females) with knee OA. High-speed video analysis and a force platform were used to record sagittal view lower extremity kinematic data and ground reaction forces. Increased body mass index (BMI) was significantly related to both decreases in walking velocity and knee maximum extension. There were no significant relationships between BMI and any of the hip or ankle kinematic variables. BMI was directly related to vertical force minimum and maximum values, vertical impulse, and loading rate. Increases in braking and propulsive forces were significantly correlated with increased BMI. Maximum medially and laterally directed ground reaction forces were positively correlated with BMI. Our results suggests that, in subjects with knee OA, obesity is associated with an alteration in gait.