Group 1 - Runners will be assigned identical training sessions over a 7-day period and will perform these runs in two pairs of the same assigned neutral-cushioned running shoe (Nike Pegasus). The weekly training volume will increase on a weekly basis in order to progressively increase training load in preparation for the half-marathon event.

Group 2 - Runners will perform a variation of workouts, consisting of interval/speed work, tempo runs, and long-slow distance runs throughout each 7-day period. As with Group 1, weekly training volume will increase on a weekly basis. Runners in Group 2 will perform these runs in two pairs of the same assigned neutral-cushioned running shoe (Nike Pegasus).

Group 3 - Runners will be assigned identical training sessions over a 7-day period but will alternate use of two different models of running shoes across successive workouts (Nike Pegasus and Nike Zoom Streak). The Zoom Streak has 10mm less midsole material, a less supportive heel counter and more flexible forefoot providing a more responsive feel to the runner.

Group 4 - Runners will be assigned a variation of workouts throughout each 7-day period and will alternate use of two different models of running shoes across successive workouts (Nike Pegasus and Nike Zoom Streak).

Runners will perform a variation of workouts, consisting of interval/speed work, tempo runs, and long-slow distance runs throughout each 7-day period

When an participant misses 3 consecutive assigned running workouts.

11-point numerical rating scale of overall pain associated with running

Numerical rating scale for pain at selected anatomical locations: gluteal, low back, groin, thigh, hamstring, knee, calf, Achilles, ankle, foot.