Acute hamstring strain injuries are common in sports that involve high-speed skilled movements, including but not limited to, sprinting, kicking, and jumping. It is generally believed that it happens during the terminal swing phase of the gait cycle, which is the eccentric phase of the hamstring where the hip is in flexion and the knee in extension.
Think of it as if you’re kicking a ball as hard as you can, and the torque generated by the quads is more than what the hamstrings can handle to stop the knee from going into hypertension! Here where the proximal part of the hamstring fibers get over loaded and “collapse”.
Non traumatic injuries occur when tissue capacity can not meet the physical demand of the movement required to be done. To simplify it more, check out the equations below:
Tissue capacity < load = injury
Tissue capacity > load = rehab.
Tissue capacity = load = progress/injury prevention
A number of potential risk factors have been proposed for hamstring strain, among them fatigue, lack of mobility, insufficient warm up, or imbalance in H:Q ratio (hamstrings to quadriceps muscular strength ratio) as it’s suggested that the quadriceps should be 20% stronger to minimizing the risk of knee injuries.
Certain types of hamstring injuries are more likely to require prolonged rehabilitation and delayed return to play, As studies showed 1/3 of the hamstring strains reoccurs in the first 2 weeks of returning to sport.
An emphasis on neuro-muscular control and eccentric strengthening of the involved muscles is suggested for the successful return to sport after injury.
Hamstring injuries showed great response to Nordic exercises in terms of rehabilitation or “injury prevention” as the combination of closed kinetic chain exercise and eccentric loading has the highest impact on any joint or muscle when it comes to building strength.
From “optimal loading” perspective, every injury should be tackled from difference angles. From clinical experience, I’d highly suggest RDL (Romanian deadlift) to take a part in the rehabilitation program as soon as the client can handle it. RDL and the variations of it must be involved in any treatment plan for the lower limbs, at least in my opinion, as it loads the gluteal muscles as well as the hamstrings unilaterally and it forces them to fire in integration, and that’s what we need! Integration of movement. It’s pointless to work on an injured structure to be strong in isolation without working on integrating it with the surrounding joints.