Running on a road for fitness, sport, or recreation poses unique challenges to the runner, one of which is the camber of the surface. Few studies have examined the effects of camber on running, namely, kinematic studies of the knee and ankle. There is currently no information available regarding muscle response to running on a cambered road surface. The purpose of this study was to investigate the effects of a cambered road on lower extremity muscle activity, as measured by electromyography in recreational runners. In addition, this study examined a true outdoor road surface, as opposed to a treadmill surface. The mean muscle activity of the tibialis anterior, lateral gastrocnemius, vastus medialis oblique, biceps femoris, and gluteus medius were studied. Fifteen runners completed multiple running trials on cambered and level surfaces. During the stance phase, mean activities of tibialis anterior, lateral gastrocnemius, and vastus medialis oblique were greater on the gutter side than the crown side. There were no differences in mean muscle activity during the swing phase. The findings of this study suggest that running on a road camber alters the activity of select lower extremity muscles possibly in response to lower extremity compensations to the cambered condition.
Birgit Unfried, Arnel Aguinaldo and Daniel Cipriani
Arnel Aguinaldo and Andrew Mahar
This study evaluated the effects of running shoes—with two types of cushioning column systems—on impact force patterns during running. Kinematic and ground reaction force data were collected from 10 normal participants wearing shoes with the following cushions: 4-column multicellular urethane elastomer (Shoe 1), 4-column thermoplastic polyester elastomer (Shoe 2), and 1-unit EVA foam (Shoe 3). Participants exhibited significantly lower impact force (p = .02) and loading rate (p = .005) with Shoe 2 (1.84 ± 0.24 BW; 45.6 ± 11.6 BW/s) compared to Shoe 1 (1.94 ± 0.18 BW; 57.9 ± 12.1 BW/s). Both cushioning column shoes showed impact force characteristics similar to those of a top-model running shoe (Shoe 3), and improved cushioning performance over shoes previously tested in similar conditions. Alterations in impact force patterns induced by lower limb alignment and running speed were negligible since participants did not differ in ankle position, knee position, or speed during all shod running trials. Ankle plantarflexion, however, was higher for barefoot running, indicating an apparent midfoot strike. Mechanical testing of each shoe during physiologic, cyclic loading demonstrated that Shoe 3 had the greatest stiffness, followed by Shoe 2 and Shoe 1. Shoe 1 was the least stiff of the two shoes with cushioning column systems, yet it displayed a significantly higher impact loading rate during running, possibly due to rearfoot motion alterations induced by the stiffer shoe. This study showed that even in similar shoe types, impact force and loading rate values could vary significantly with midsole cushion constructions. The findings of this study suggest that using these newer running shoes may be effective for runners who want optimal cushioning during running.
Arnel L. Aguinaldo, Janet Buttermore and Henry Chambers
High rotational torques during baseball pitching are believed to be linked to most overuse injuries at the shoulder. This study investigated the effects of trunk rotation on shoulder rotational torques during pitching. A total of 38 pitchers from the professional, college, high school, and youth ranks were recruited for motion analysis. Professional pitchers demonstrated the least amount of rotational torque (p = .001) among skeletally mature players, while exhibiting the ability to rotate their trunks significantly later in the pitching cycle, as compared to other groups (p = .01). It was concluded that the timing of their rotation was optimized as to allow the throwing shoulder to move with decreased joint loading by conserving the momentum generated by the trunk. These results suggest that a specific pattern in throwing can be utilized to increase the efficiency of the pitch, which would allow a player to improve performance with decreased risk of overuse injury.