title: Lower limb muscle activity during forefoot and rearfoot strike running techniques.
abstract: OBJECTIVE
  Distance running offers a method to improve fitness but also has a risk of lower limb overuse injuries. Foot strike technique has been suggested as a method to alter loading of the lower limb and possibly minimize injury risk. However, there is a dearth of information regarding neuromuscular response to variations in running techniques. The purpose of this investigation was to compare the EMG activity that occurs during FFS running and RFS running, focusing on the biceps femoris, semitendenosis, rectus femoris, vastus medialis oblique, tibialis anterior (TA), medial head of gastrocnemeus (MGas), lateral head of gastrocnemius (LGas), and soleus.
  
  
  METHODS
  healthy adults (6 male, 8 female; age, 24.2 ± 0.8 years, height 170.1 ± 7.8 cm; mass 69.8 ±10.9 kg; Body Mass Index 24.1 ± 3.0 kg·m2) participated in the study. All participants performed a RFS and FFS running trial at 8.85 kph. A 3D motion capture system was used to collect kinematic data and electromyography was used to define muscle activity. Two-tailed paired t-tests were used to examine differences in outcomes between RFS and FFS conditions.
  
  
  RESULTS
  The ankle was significantly more plantarflexed during FFS running (p = .0001) but there were no significant differences in knee and hip angles (p = .618 & .200, respectively). There was significantly less activity in tibialis anterior (TA) (p < .0001) and greater activity in the MGas (p= .020) during FFS running. The LGas and soleus did not change activity (p = .437 & .490, respectively).
  
  
  CONCLUSIONS
  FFS running demonstrated lower muscular activity in the TA and increased activation in the MGas.
  
  
  CONCLUSIONS
  FFS and RFS running have the potential to off-load injury prone tissues by changing between techniques. However, future studies will be necessary to establish more direct mechanistic connections between running technique and injury.
authors.affiliation: Department of Physical Therapy, Alabama State University, Montgomery, AL, USA.
authors.forename: Lindsey L
authors.initials: LL
authors.lastname: Landreneau
authors.affiliation: Department of Physical Therapy, Alabama State University, Montgomery, AL, USA.
authors.forename: Kayla
authors.initials: K
authors.lastname: Watts
authors.affiliation: Department of Physical Therapy, Alabama State University, Montgomery, AL, USA.
authors.forename: Jill E
authors.initials: JE
authors.lastname: Heitzman
authors.affiliation: Department of Prosthetics and Orthotics, Alabama State University, Montgomery, AL, USA.
authors.forename: W Lee
authors.initials: WL
authors.lastname: Childers
keywords: Electromyography (EMG); kinematics; neuromuscular adaptation