Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.     

Peer‐Mediated Instruction in Inclusive Secondary Social Studies Learning: Direct and Indirect Learning Effects

Ten inclusive middle school social studies classes, including 133 general education students, and 24 students with mild disabilities (21 with learning disabilities and 3 with emotional disabilities), were assigned at random to a traditional instruction condition, or an experimental condition involving classwide peer tutoring with specialized materials and parent training. After 18 weeks of instruction, posttest data revealed that students in the experimental condition gained significantly more than students in the traditional instruction condition. These effects were observed on content included in the tutoring intervention, as well as on related content that was taught but not included in the tutoring intervention. Results are discussed within the context of recent research on inclusive secondary content area instruction.