For those who have read Charlie’s thoughts on resisted sprinting, one concept he was a proponent of was a waist harness.
In the current Journal of Strength & Conditioning Research(Bentley et al., March 2016 Volume 30, Number 3), a study looked at biomechanical factors of an un resisted sprint to resisted sprints with both shoulder and waist harness.
“In summary, waist harness seem to be the most suitable attachment point for the acceleration phase of sprinting. Sled towing with these attachment points resulted in fewer kinematic alterations and greater net horizontal impulse when compared to the shoulder harness.”