Review written by Dr Teddy Willsey info


Hamstring muscle strains are one of the most common injuries seen amongst field athletes who routinely sprint at near maximal speeds. The injury most frequently occurs at the musculotendinous junction. The high rate of hamstring injury and reinjury along with the ambiguity of return to play (RTP) criteria represent a significant challenge in the sporting world.

Recent advancements in MRI diagnostics have shed light on the high frequency of intramuscular tendon hamstring injuries. Currently, there is no consensus as to an ideal course of treatment for this subtype of hamstring injury. In the past, intramuscular hamstring tendon injury was oftentimes repaired surgically with underwhelming and inconsistent outcomes.

In the quest to constantly improve sports medicine treatment and explore the least invasive measure first, this case study examines the rehabilitation of an English Premier League footballer who suffered a proximal hamstring intramuscular tendon injury during competition.



The conceptual goal of this rehabilitation was to mechanically load the injury site and improve tensile strength, elastic stiffness, and cross-sectional area of the injured tissue. There was a clear progression from isometrics at shortened positions to dynamic exercises at increasing muscle lengths and load. As with many lower extremity rehabilitation protocols, exercise progression typically goes from unloaded to loaded, and bilateral to single leg. The goal is to increase stress on the injured area over time.

Isometric exercises were performed as maximal voluntary contractions in cluster sets of 3-5 sets at 3-5 second holds. The theoretical basis is to provide cyclical high strain magnitudes to increase tendon stiffness, reduce strain, and enhance force development. A force plate was used to determine load progression. For example, at week 7 the criterion for phase progression was peak force asymmetry being less than 10% in the 90/90 isometric supine heel drive (hip flexed to 90, knee flexed to 90, contralateral hip and knee extended - see video).

Exercise selection was thoughtful and specific. Gluteal bridges were one of the mainstay movements in this rehabilitation progress. They were progressed in three ways: increasing lever arm, increasing load, and elevating the feet. The Romanian deadlift was the primary hip dominant weight bearing exercise. It was progressed from bilateral to single leg, with the goal of improving hip symmetry and increased recruitment of the injured muscle group. The reverse lunge was the primary knee dominant movement selected, with progressions in range of motion and load. The reverse lunge was noted as an exercise that has a strong dynamic correspondence to high speed running gait.

The most unique factor of this rehabilitation protocol was the extended time period focused on high speed movement. Re-acclimatization to plyometrics, including high speed running and jumping began at week 10. Prior to week 10, the speed of eccentric contraction was progressively increased to mimic the fast stretch-shortening cycle the hamstring is under during high speed running.

Force plate testing was used to measure hamstring contractile speed. Peak force development was measured at a quick impulse: only 100ms of time. This measurement is thought to be a strong indicator of rate of force development, thus an objective measure for positive musculotendinous adaptations and the contraction speed necessary for high speed running.


The player returned to competition in 120 days (4 months) and remained injury free 13 months later. The process of increasing running exposure began at week 10 and continued all the way through week 17. This player actually achieved a

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