However, this hypothesis needs to be tested more thoroughly. This study therefore used a randomized controlled study design to test three hypotheses about the effects of running in minimal shoes on the arch and intrinsic muscles of the foot. First, we tested if runners who transitioned from standard running

shoes to minimal footwear landed with more of an MFS or FFS. Second, we tested if runners who adapt to a minimalist shoe increased the ACSA and muscle volume (MV) of the three main intrinsic muscles of the longitudinal arch. These include the abductor hallucis (ABH), flexor digitorum brevis (FDB), and abductor digiti find protocol minimi (ADM), all of which run like longitudinal bowstrings from the calcaneus to the metatarsals or phalanges.22 These most superficial intrinsic plantar muscles span much of the long axis of the foot and are easiest to measure using MRI as it distinguishes well between bone and soft tissues. Finally, we tested the hypothesis that runners who transitioned to minimal support footwear developed higher, stronger arches. Thirty-three healthy adults (17 males, 16 females) were solicited from the Cincinnati area. Inclusion criteria required an average of 30 running miles per week (48.3 km/week) in standard running shoes for no less than 12 months. Exclusion resulted

from minimal Veliparib molecular weight shoe running, barefoot activities, or any lower limb injury within the previous year that restricted running for more than 5 consecutive days. Subjects were randomly assigned to one of two study groups (Table 1). The control group (n = 16) ran only in conventional footwear with plastic arch supports and a cushioned heel offset approximately 12 mm from the midsole height

at forefoot to midsole height at heel. Footwear among control subjects was self-selected, and all shoes met the standard design requirement. Shoe brand and model were individually assessed according to the criteria and recorded for each participant. DNA ligase Subjects assigned to the experimental group (n = 17) transitioned from standard running footwear to minimal support footwear that lacked built-in arch support, provided reduced cushioning, and had a forefoot-heel offset of 4 mm or less. Minimal models included the New Balance® Road Minimus 10 (4 mm offset; New Balance®, Boston, MA, USA) or Merrell® Pace/Trail Glove (0 mm offset; Merrell®, Rockford, MI, USA). Subject and minimal shoe model were randomly paired. All participants were asked to follow one of two custom designed training programs. Those who ran only in conventional shoes maintained a weekly regimen of 30 shod miles ( Appendix 1). Those transitioning to minimal shoes matched weekly mileage with the control group while gradually increasing the percentage of minimally shod miles ( Appendix 2). In an attempt to prevent injuries associated with abrupt transition to minimal support footwear 4 and 23 our transitioning protocol eased runners into greater minimal footwear mileage across a longitudinal 12-week study.