Following up on my previous post “Hamstring Strain Injuries: Examination”, we will be reviewing a framework for care of these injuries beginning with early stage interventions in this post. For the sake of simplicity we will assume that early stage care includes a timeline of date of injury, through the inflammatory phase, and into the proliferative phase of healing. (~1-2 weeks)[1] depending on injury severity. The degree of injury is somewhat determinant of the length of each stage of rehabilitation. Appreciate that these stages will be lengthier for higher grade, more severe injuries.
These stages occur more on a continuum rather than with definitive set start and end points. Additionally, clinicians are not always afforded the opportunity to initiate care within the first few days of injury. Oftentimes patients come into the clinic with recurrent or persistent strains and pain resulting from trying to push through these injuries. In these instances clinicians must determine where the patient is entering these stages and how best to organize a rehabilitation plan from that time point forward. In these situations it is necessary to take a wider scope view to mitigate risk and successfully prepare the patient for the demands of their sport upon returning to play.
What matters?:
Recalling the post detailing examination, we established several KPIs to track progress during HSI rehabilitation. If you missed this post check it out here.
Chief goals of early-phase hamstring strain rehabilitation include reducing symptom acuity, restoring active knee extension, initiating hamstring loading, restoring mobility, and maintaining functional status within the patient’s tolerance.
The Role of Pain in Hamstring Strain Rehabilitation:
Pain is a common part of rehabilitating many injuries and plays a vital role in terms of protection early in healing. While there is a time and place for respecting pain and staying within pain-free limits (acute phase), there is evidence that allowing appropriate levels of pain may be beneficial in restoring function sooner in the rehab process. A study by Hickey et al.[2] found no difference in RTP time between pain-free and pain-threshold guided rehabilitation. The study observed a better recovery in hamstring strength for the pain-threshold group, biceps femoris long head fascicle length for the pain-threshold group, and no difference in re-injury rates between the groups. Personally, I discuss with patients that a pain intensity of 3 or less out of 10 is okay within activity progressions. Allowing for pain-threshold rehabilitation allows for a greater recovery in function sooner and similar RTP times.
Symptom Management:
Should you be evaluating a patient early on following a HSI they will likely have complaints of reduced ROM/mobility, stiffness, swelling, bruising, and pain. These limitations impair their ability to not only perform sporting activity, but even basic activities such as walking, stair negotiation, and general mobility.
Within our tool boxes as PTs we have passive interventions such as soft-tissue mobilization and modalities that may assist in reducing pain, swelling, and stiffness. These are appropriate to implement early in care. Personally, I’d recommend lighter forms of soft tissue in more acute situations (i.e. effleurage). While I think DN may be helpful, and even requested by patients, I feel it may be worthwhile to defer it during the inflammatory phase of healing. As healing progresses and rehabilitation moves toward the middle stage dry needling may be more productive.
Implementation of manual therapy techniques provides a natural situation where the area of tenderness can be frequently monitored during early phase rehabilitation. As healing progresses we may see the area of tenderness decrease in size and the overall sensitivity reduced. For home management I feel it appropriate to educate the patient on the use of a foam roller or other tool (lacrosse ball) to mimic the effects of soft tissue and increase self-efficacy in care. It is important to note that these techniques are not breaking up scar tissue or adhesions and are simply methods of creating a neurophysiological effect that can lead to reduced tone, decreased symptom sensitivity, and perhaps lessen pain.
Restoration of Hamstring Mobility:
As determined by the AKE test, a key goal early in care will be to restore hamstring mobility to within normal limits or symmetrical relative to the uninvolved limb. Restoration of ROM provides the athlete with the requisite amount of movement to complete functional tasks (i.e. walking, running, jumping, etc.). This may be accomplished through light active mobility and ROM tasks. Some of these may include something as simple as prone knee bends, hamstring ball curls for knee ROM, and active hamstring stretches with slack allowed at either the hip or the knee. One of my favorites to go to is the active hamstring stretch or “hamstring flosser” (see below).
This wonderfully simple activity allows the patient to be in control of how much stretch is placed on the hamstring while allowing some level of slack at the knee. I instruct the patient to keep it within painful limits and to bump into pain or stiffness but not necessarily through it.
Recall the mechanism of injury associated with these injuries as being a “stretch injury.” With this in mind throughout the early to mid-phase of care avoid passive, prolonged stretching. While this may feel good in the moment to patients, it is not productive and could slow the early phases of healing.
Restoring Basic Ambulatory Mobility:
As symptoms allow, clinicians should reintroduce all basic patterns of movement to patients. In early-phase rehabilitation this will take the form of ambulation and marching drills in multiple planes. These patterns are listed in table 1. When effectively sequenced a low aerobic effect may be achieved and serve as an active warm up ahead of other interventions. Clinicians may build volume and repetition over the course of a few sessions. Consistency with these “turf drills” provides the means to progress to skipping and running progressions as care moves into the mid- to later phases of rehabilitation.
| Ambulation and Marching Patterns | Linear Lateral Cross over Cross under Grapevine/Carioca |
Initiating Hamstring Strengthening:
Hamstring strength and performance deficits are established at examination. It is important to initiate progressive loading of the hamstring as soon as reasonably possible in the form of a standard loading progression (figure 1).[3] Evidence shows that including eccentric strengthening in a rehab program for HSI reduces risk of re-injury and improves functional outcomes.[3] While high intensity eccentric loading is inappropriate in early stage rehab, there are modifications that allow for exposure to these movements and prepare athletes for mid- to late stage rehab where this will be a staple. Clinicians must quantify intensity for athletes through each of these phases. Some options include perceived intensity, RPE, or pain-threshold.
The degree of injury will impact the speed with which you progress an athlete through each of these phases. A higher degree of injury requires a more careful and slower exposure into each of these loading phases. A lower degree of injury should allow for a quicker transition between these phases.
Hamstring position, speed of contraction, and loading intensity are aspects of exercise selection and dosage that must be considered throughout the rehabilitation process. Exercises should progress from shortened to lengthened hamstring positions, slower to faster contraction speeds, and from lower to higher load intensities as rehabilitation progresses. Therapists should screen for patient treatment response in terms of pain, fatigue, and reactive symptoms in the form of exercise-related soreness or new onset of pain. I’ll touch more on these characteristics of exercise progression in a following post detailing mid- and late phase rehabilitation.
See the below table 2 detailing a basic exercise progression for hamstring loading in early-stage rehabilitation.
| Hook-lying hamstring isometric | Hamstring in very shortened position, self-guided intensity with pain-threshold |
| Standard Bridge Isometrics | In bilateral or unilateral positions as tolerated. Dosage may start at 2x10x5 sec progressing to 3x30s. Hamstring in slightly lengthened position |
| Standard Bridge Eccentrics | Bilateral concentric to unilateral eccentric in relatively shortened position. Dosage 2-3×10-15 |
| Elevated Bridge Isometrics | See above, key difference is that the hamstring is now in mid-range, lengthened position |
| Elevated Bridge Eccentrics | See above eccentrics, similar dosage. |
| Bridge with eccentric slider phase | This activity may be completed in a bilateral or unilateral position. Allows the hamstring to move through the eccentric phase from a flexed to extended knee position. Dosage of 2-3×10-15 as tolerated. A great exercise to key clinicians into an athlete’s preparedness to move into mid-phase activities. |
Aerobic Activity and Conditioning: Early Phase:
The initiation of light aerobic exercise based on activities tolerated during the examination promotes systemic blood flow to assist in the healing process and helps to maintain conditioning levels in the athlete.
Aerobic activity may initially take the form of a walking program in some injuries. Biking or a linear jogging program that allows for progressive intensity throughout the plan of care are also viable options depending on what the athlete tolerates. In a more significant injury these may need to be deferred in favor of true rest to allow the inflammatory phase to run its course. As symptoms recede and functionality improves the initiation of aerobic activities is highly recommended as the healing process enters the proliferative and remodeling healing phases.
Maintenance of Other Strength and Conditioning:
As acuity dissipates I recommend maintaining strength and conditioning programming for the upper and lower body using activities with less hamstring involvement. It is reasonable to discuss the idea of pain-threshold based activities so that training may continue and conditioning levels are maintained. This will assist in setting the patient up for success in later stages of rehabilitation and RTS.
Sample Session for Early-Stage Hamstring Rehabilitation:
| Manual Therapy | Effleurage, soft-tissue mobilization, perhaps dry needling (as indicated) |
| Mobility | Active hamstring mobility and light activation, maintenance of surrounding joint potentials |
| Locomotive | Turf drills progressing from ambulation to marching, eventually jogging type activities and skipping as tolerated, multi-planar activities for variability and application of movement |
| Hamstring Loading | Exercises that load the hamstrings (shortened to lengthened positions) starting with isometrics and progressing to eccentrics within pain-threshold |
| Conditioning | Biking or jogging aerobic activity 10-20 minutes, maintenance of S&C programming with non-hamstring dominant movements (i.e. circuits, traditional loading, etc.) |
Conclusion:
Early-stage interventions should be geared toward setting the patient up for success in later stages. Important conversations include education on the role of inflammation in healing, the appropriate level of intensity for activities, the role of pain and pain-threshold in rehab, and short-term goals for early-stage rehab. Exit criteria for progressing into mid-phase rehabilitation include: a normalizing AKE test, improving symptoms in the form of lesser symptom sensitivity and a smaller area of tenderness, restoration of pain-free ambulation, and the ability to tolerate isometric loading in both shortened and lengthened positions.
Citations:
[1] Laumonier T, Menetrey J. Muscle injuries and strategies for improving their repair. J Exp Orthop. 2016;3:15. https://doi.org/10.1186/ s40634-016-0051-7
[2] Hickey, J. T., Timmins, R. G., Maniar, N., Rio, E., Hickey, P. F., Pitcher, C. A., Williams, M. D., & Opar, D. A. (2019). Pain-free versus pain-threshold rehabilitation following acute hamstring strain injury: A randomized controlled trial. Journal of Orthopaedic & Sports Physical Therapy, 1–35. https://doi.org/10.2519/jospt.2019.8895
[3] Martin, R. L., Cibulka, M. T., Bolgla, L. A., Koc, T. A., Loudon, J. K., Manske, R. C., Weiss, L., Christoforetti, J. J., & Heiderscheit, B. C. (2022). Hamstring strain injury in athletes. Journal of Orthopaedic & Sports Physical Therapy, 52(3). https://doi.org/10.2519/jospt.2022.0301
