16 Weeks of Progressive Barefoot Running Training Changes Impact Force and Muscle Activation in Habitual Shod Runners
Condition: Barefoot Running
Study type: Observational

Summary: 
      The purpose of this study was to evaluate the influence of 16 weeks of progressive barefoot
      running training on impact force and muscle activation in habitual shod runners. Habitual
      shod runners were tested barefoot (BF) and shod (SH), before and after 16 weeks of
      progressive barefoot running training. Tests consisted of running on instrumented treadmill
      at 9 km/h, for 10 minutes in each experimental condition. Nine data acquisitions (10 s) of
      vertical ground reaction force (VGRF) and electromyographic (EMG) signal were conducted in
      each experimental condition, for each test.
    

Detailed description: 
      Short-term effects of barefoot and simulated barefoot running have been widely discussed in
      recent years. Consequences of adopting barefoot running for a long period, e.g. as training
      strategy, still remain unknown. The present study evaluated the influence of 16 weeks of
      progressive barefoot running training on impact force and muscle activation in habitual shod
      runners. Habitual shod runners were tested barefoot (BF) and shod (SH), before and after 16
      weeks of progressive barefoot running training. During the 16 weeks of training, participants
      kept their normal running training routine (wearing shoes), while they were introduced
      progressively to BF condition. Three training sessions were performed per week. Barefoot
      training started with 5% and ended with 20% of their weekly training volume (WTV) being
      performed without shoes. Soft surfaces (i.e. sand and grass) were adopted in the beginning of
      training (week 1 to 8). From week 9 to 16, participants mixed soft with harder surfaces, as
      treadmill and asphalt, to accomplish the training. Training sessions were prepared by
      professionals, researches and participants together. All training sessions were supervised by
      the researchers. Tests consisted of running on instrumented treadmill at 9 km/h, for 10
      minutes in each experimental condition. Each session test started with participants
      performing a maximum voluntary isometric contraction (MVIC) test for each muscle of interest.
      The MVIC protocol consisted of 4 movement trials for each muscle: 2 submaximal trials of 10
      seconds; 1 maximal trial of 5 seconds; and 1 maximal trial of 10 seconds. Then, a 5-minute
      period of warm-up at self-selected speed was performed on a treadmill. After that,
      participants ran (at 9km/h) during 10 minutes on an instrumented treadmill in both barefoot
      and shod conditions. Participants had a 2-minute interval between each trial while
      experimental condition was changed. The VGRF of both legs and EMG signal of tibialis anterior
      (TA), gastrocnemius lateralis (GL), long head of biceps femoris (BCF), rectus femoris (RF)
      and vastus lateralis (VL) of the right leg of each volunteer were obtained. These muscles
      were chosen due to their importance and contribution to running. For shod trial, runners wore
      their own habitual running shoes. All shoes were in good conditions of use and had similar
      characteristics of construction.
    

Intervention name(s): Barefoot training; Shod training
Intervention type(s): Other; Other
Intervention description(s): During 16 weeks, habitual shod runners kept their normal running training routine (wearing shoes), while they were introduced progressively to BF condition. Three training sessions were performed per week. Barefoot training started with 5% and ended with 20% of their WTV being performed without shoes. Soft surfaces (i.e. sand and grass) were adopted in the beginning of training (week 1 to 8). From week 9 to 16, participants mixed soft with harder surfaces, as treadmill and asphalt, to accomplish the training.; Running training planned individually to each runner, according to their physical fitness, and performed with shoes.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Habitual shod runners (recreational runners without experience in barefoot and/or
        minimatist running)