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Peak Performance Physical Therapy & Sports Training EVIDENCE-BASED PRACTICE UPDATE September 2020 Rachele Jones PTA, ATC, CAFS You decide…. Patient Scenario: A high school soccer athlete comes to you for what they think is a strain in their hamstring. While playing they felt a small “twang” or “pop” in their mid-belly at the posterior thigh and are having pain with completing knee extension, especially in sitting, with bending over, taking long strides, and cannot jog. Your clinical exam is consistent with a biceps femoris muscle strain. You’re ordering Physical Therapy. Clinical Decision Making… How do I decide where to send the patient? Will their rehab be essentially the same wherever they go? Are generic HS exercises adequate or will they customize exercise stresses for my patient to target specific injured tissue for functional demands? Will proximal kinetic chain factors be tested and addressed to handle underlying risk factors? Summary: Physicians regularly are charged with making decisions on best practices regarding hamstring strains for overall care, specifying prescription orders vs releasing full trust to the PT to “figure things out and do what’s best”, and how referrals to PT are decided. The authors present data that shows in a group of male soccer athletes over 1.5 seasons there was a 20% reduction in HS strains for those sprinting with 10% greater gluteal activity during early front swing phase and 6% reduction for those with greater trunk/core activity during backswing phase of sprinting during pre-season testing. The general concept is that proximal activation of those muscles/groups appears to be at least somewhat protective against HS strains and therefore must be considered as a potentially important component of rehabilitation. It is surprising they found no significant differences for late swing and early contact phase, where the HS forces would intuitively be higher and at greater risk of strain. It must be remembered that EMG demonstrates neurologic activation but is not proportional necessarily to actual force production. The study does fail to indicate how exactly these findings can be put into practical application during Physical Therapy. This would require specific research to determine any best practices on specific exercises that promote EMG evidenced activation along with experimental cause-effect determination if injuries are, in fact, prevented using specific training practices and if reinjury is avoided using similar concepts during rehab. Current Evidence: Joke Schuermans, et al. Proximal Neuromuscular Control protects against hamstring injuries in male soccer players. The American Journal of Sports Medicine 2017; 45 (6) 1315- 1325. Background: Hamstring injuries remain the highest incidence and the most detrimental functional repercussion in male soccer athletes. Proximal neuromuscular control (“core stability”) is considered to be a key importance to primary and secondary hamstring prevention although scientific evidence is currently nonexistent. Method: Sixty amatuer soccer players participated in pre-season testing using multi-muscle surface electromyography (sEMG), assessing medial/lateral hamstrings, gluteals, and trunk erector spinae and int/ext obliques(later analyzed as a group) during maximal acceleration to full speed sprinting. Time frame of 1.5 seasons was evaluated and athletes would self-report. Follow up of the hamstrings, gluteals, and trunk muscle activity during airborne and stance phases of acceleration were evaluated and statistically explored for possible causal association with self-reported injury occurrence and absence from sport during follow up. Results: Players that did not experience a self-reported injury to the hamstring, showed an increase in gluteal muscle activity during (early) front swing phase and higher trunk muscle activity during backswing of sprinting. The risk of hamstring injury lowered by 20% from A 10% increase in gluteal activity during front swing and decreased by 6% with a 10% increase in trunk muscle activation during backswing. AUTHOR’S Conclusion: Higher amounts of gluteal and trunk activity were shown during airborne phases during sprinting which was associated with lowering the risk of hamstring injuries. This provides a basis for improvement on rehabilitation and prevention focusing on the increasing neuromuscular control of the glut and trunk muscles during sport specific activities ( sprinting drill, and agility drills). Peak Perspective: Looking at the anatomy and physiology of the hip, the hamstrings ( bicep femoris, semimembranosus, semitendinosus), gluteus maximus, and the adductor magnus are all muscles that produce hip extension or decelerate hip flexion. Hip extension force occurs with deceleration of late swing knee extension and hip flexion, early stance phase as a hip extensor to produce forward propelling momentum, and in early backswing as hip extension and knee flexion occur. While not actually defined by Schuermans et al, back swing is the moment from toe off until the leg reaches maximum extension behind the body. Front swing is the moment when the leg begins to swing forward and ends just before heel strike. One would expect the greatest demand on hamstrings to be late swing and early stance phase. This study showed that those who eventually reported hamstring strains showed sprint function tendencies for lesser gluteal and trunk activation during NWB swing phases (back swing and early front swing). This may warrant modifying current rehab practices if these findings were to be confirmed with further research. Until then it is likely premature. Examining pre-injury functional patterns for potential risk factors is valuable. The limited size of this study and number of injuries reported along with the fact injuries were self-reported, and especially that the mechanism was not specified as sprinting related necessarily all contribute to uncertainty whether this really does rise to the level of evidence driving a change in physician treatment expectations of physical therapists and athletic trainers for hamstring injury care. For example, what if the strain was related to a misstep or slide tackle contact or unexpected perturbation during a “50-50 ball”? It would become a bigger leap of faith that sprinting sEMG findings were reflective of greater risk during that injury mechanism. One issue is no reporting as to when the athlete's injury occurred, what was the mechanism of injury, (whether during running or contact with another player), the severity of the injury, and what made them more susceptible to injury. With this information being withheld was can not correlate what areas to concentrate on whether more linear patterns or the unexpected which would be best for prevention or quicker return to play status. As a measure of nerve activation, sEMG, in this study, resulted in findings opposite of what we would have expected, showing that the hamstring was most responsive in the backswing and early swing phases. Even if that were accepted to be true - studies have not been done to demonstrate which exercises are best employed to activate the gluteals and proximal trunk/core during swing phase, preferentially to other muscles, for prevention and return to play training. Then a “causal” relationship would need to be shown between whatever specific activation drills might be done, the effective improvement of gluteal and core activation in sprinting, and a reduction in hamstring strains. The authors seem a bit quick here to accept correlational level findings as likely causal in their conclusion and recommendations. Regardless, the findings suggest physicians and therapists might consider more open chain exercises for stimulating gluteal and trunk/core activation for swing phase (rather than a main focus on WB hamstring work), in order to improve the timing activation of these muscles/groups in running like positions/movements for swing phase. This is an area we need to give further consideration to and develop exercise strategies for. Since these findings, however, remain too early to be prescriptive for “best practices” of hamstring strain recovery, the biomechanically relevant considerations of understanding when the hamstring is under maximal tension (nearing and at heel strike) and when the greatest contractile demands and lever arm loads are occurring can and should remain a key principle to rehab and to treatment expectations from physicians. At Peak Performance we find that using a “hamstring strain” protocol or exercise series consistent across all patients is not effective. Strains may be more medial or lateral. They may involve more proximal fibers vs more mid-belly or even distal muscle-tendon junction. Customizing each exercise to the deficits and symptoms of the patient and to the demands of what activity/sports they want to resume are critical. All three planes of motion must be tested and considered to thoroughly retrain an injured hamstring. Transitioning into specific speed-power exercises is necessary for rapid acceleration and deceleration muscle performance and helps prepare for sport specific drills and eventual return to sports. Since this study found sprinting based swing phase muscle activation to account for some risk factor, open chain loading and neuromuscular type exercises would also be appropriate. The VibePlate, a vibration platform designed to stimulate the neural system, is one tool we use oftentimes during hamstring strain recovery. A popular exercise is the Nordic Hamstring curl. While a very demanding exercise and having some limited evidence basis, aside from being very challenging and therefore stimulating, it functionally trains the hamstring’s ability to decelerate a thigh extending over a fixed lower leg. That is not typically consistent with athletic function nor definitively with injury mechanisms. Functional loading with multidirectional lunges incorporating an anterior reach with weights trains the hip extensors’ ability to effectively decelerate as would occur in planting and changing direction or using implements reaching for a ball (lacrosse, tennis, field hockey, hockey..etc). Tubing resisted terminal swing phase directly trains the hamstrings as an eccentric decelerator of knee extension + hip flexion in prep for heel strike. RDL’s and tubing based horizontal pulling based stepping drills train early stance phase hip extensor ability. All of these are also customized to include multiple planes in consideration of multilateral sport movement demands or also based specifically on injury mechanism. The case below demonstrates a patient where many of these principles were utiilzed, despite not specifically incorporating the backswing and early swing phase gluteal/core activation referenced in Schuermans' study, and this patient did extremely well - the objective tests show gluteal, hamstring and core have all improved to >100% of the uninjured side. Peak Experience: “ I feel a lot better. There’s more flexibility in my leg and I didn’t notice it at all with soccer tryouts!” “ I was able to do half field sprints, all drills and have been able to do short runs now.” HX: 15 yo female soccer player injured 5 months prior, reporting pain in the ischial tuberosity and right hamstring due to increased running mileage of 3 miles a day/ 5 days a week. Subjective: Pt reports intermittent 3/10 pain in R hamstring and ischial tuberosity after increasing mileage in preparation for the upcoming soccer season. Symptoms are increased by seated hamstring stretch , cartwheels, walking up a hill, squatting, ascending stairs, and any duration of running. Patient self reports being at 70% overall function and Lower Extremity Functional Scale 88% function Objective: Patient showed decreased overall hip mobility, ankle mobility, calf tightness, and decreased hamstring strength on contralateral limb. Hamstring range of motion significantly decreased on R. See below re Eval and Re-Eval findings. *pain Initial Evaluation (L/R ) ReEvaluation 8+ wks (L/R) Self Rating 70% overall function 90% Overall function LEFS Scale 88% 90% Pain scale max 3/10 max 3/10 - only deep squat Supine 90/90 HS length 12deg/23deg 8deg/7deg DF ROM knee extend’d 0deg/10deg 11deg/13deg Prone Single Leg FA plank NT L WB 4 sec / R WB 7 sec SL Squat - - - -> hop Squat: R* > L dyn valgus SL hop: Dyn valgus = HS isometric 9.0 kg/11.0 kg 10.7 kg/11.0 kg 6” Step up test 10# DB’s NT 30x/30x Treatment: Exercise - Mobility, strengthening, power, function… Kinetic chain stretching of hip, hamstring (HS), STJ, and calf including mulitplanar. PRE’s including NWB, WB, Impact/speed based drills, and agility - utilizing multiple angles and a proximal- - >distal and distal- - >proximal directed movement loading approaches. (Included: SL bridges, 6” step ups (gluts focus), tube resisted stepback to pull thru hip extensions in 3 paths, SLB with UE reaching for medial and lateral HS stimulus) Core work including: Incline single arm side plank with Ant-Post LE stepping, prone incline plank w LE knee hip cross to opposite hip, SLB on the Vibe Plate w weighted UE running arms for additional strength, and running progressions. Agility progressed to SL hopping in multiple directions, and incline demand during treadmill. Peak Performance is just minutes away from your patients in Penfield, Fairport, Pittsford, Brighton, Rochester and, of course, East Rochester. We promise Individualized, hands-on and biomechanically appropriate Physical Therapy for your patients. No "one-size-fits-all" approaches. We WILL go the extra mile and "dig deeper" to discover underlying causes for injury risk and delayed recovery using the most advanced Evidence Based methods available and, we’re able to make unique adjustments to exercise prescriptions to speed the return to function and to minimize or prevent symptoms from interfering. No surprises. No hassles. Confident your patient is in the right place. COME VISIT US AT 161 E Commercial St Just 1 mile off 490 exit (585) 218-0240 www.PeakPTRochester.com