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Abstract:    The aim of this study was to ascertain the effect of a six week plyometric training
 program on the RE and 3000 meter time of a group university of middle distance
 athletes. Eight club level middle distance university athletes completed a twelve
 minute sub maximal test on a treadmill and a 3000 meter maximum effort run. The
 treadmill test was completed at velocities of 12, 14 and 16kmph (each for four
 minutes). Oxygen uptake was recorded and their running economy was calculated
 for each velocity. The 3000 meter run took place on a 400 meter outdoor running
 track. Four of the participants (experimental group) then completed a six week
 plyometric training program alongside their usual training while the remaining four
 (control group) carried on with their normal training. After the six weeks all
 participants repeated the tests. A paired t-test was conducted on the results and it
 was found that the plyometric training only had a significant effect on the RE of the
 participants who completed the training at 12kmph (p=0.004) and had no effect at all
 on their 3000 meter time. It was found that six weeks of plyometric training had no
 significant effect on the RE or 3000 meter time of middle distance athletes.

Runners are often categorized as forefoot, midfoot or rearfoot strikers, but how much and why do individuals vary in foot strike patterns when running on level terrain? This study used general linear mixed-effects models to explore both intra- and inter-individual variations in foot strike pattern among 48 Kalenjin-speaking participants from Kenya who varied in age, sex, body mass, height, running history, and habitual use of footwear. High speed video was used to measure lower extremity kinematics at ground contact in the sagittal plane while participants ran down 13 meter-long tracks with three variables independently controlled: speed, track stiffness, and step frequency. 72% of the habitually barefoot and 32% of the habitually shod participants used multiple strike types, with significantly higher levels of foot strike variation among individuals who ran less frequently and who used lower step frequencies. There was no effect of sex, age, height or weight on foot strike angle, but individuals were more likely to midfoot or forefoot strike when they ran on a stiff surface, had a high preferred stride frequency, were habitually barefoot, and had more experience running. It is hypothesized that strike type variation during running, including a more frequent use of forefoot and midfoot strikes, used to be greater before the introduction of cushioned shoes and paved surfaces.