Groin and hamstring injuries are two of the most common athletic injuries and are rampant in both the professional and recreational athlete. The causes of these injuries are continually misunderstood, and all-too-often the solution to these injuries is to stretch the respective muscles and hope for the best. Unfortunately, often to the detriment of the athletes, this approach seldom works.
The key to solving these injuries lies not in attacking the problematic area but rather in addressing the faulty mechanics that preceded the injury.
While many causes of hamstring and groin injuries have been postulated (dehydration, mineral imbalances, muscle imbalances in quadriceps to hamstring strength, to name a few), there are a few precipitating events that relate to virtually 100 percent of these injures. These include the following:
- Poor lumbo-pelvic-hip stabilization
- Improper control of the femoral head in the socket
- Improper training methods
Each of these will be discussed in more detail throughout this article.
While at first glance hamstring and groin injuries may seem unrelated, a look at the functional anatomy reveals that these injuries are directly related to hip and pelvis mechanics. There are two key anatomical regions that must be considered when dealing with groin and hamstring injuries; the lumbo-pelvic-hip complex (LPHC) and the thoracic canister (ThC).
The LPHC serves as a functional bridge between the trunk, upper and lower extremities. It is subject to a complex array of forces and provides a stable platform in which to generate power such as when throwing a punch or kicking a ball. The ThC includes the lower thoracic spine (T6-12), ribs, lumbar spine and pelvis. It functions as the key region of respiration as well as spinal rotation while the lumbar spine and pelvis including the SIJ function as areas of stability.
How do we know this? Just consider the number of joints contained within these regions. The LHPC contains 23 total articulations (18 in the lumbar spine, two hips, two SIJ and one at the pubic symphysis) while just the lower six thoracic levels of the ThC contain 62 joints between the vertebrae and ribs. The large number of articulations in the thoracic spine dictates that it must be a mobile area to allow for proper respiratory function as well as trunk rotation while the relatively fewer number of joints and larger size of the lumbar spine and pelvis suggest its role is more in stability.
Therefore, any strategy that disrupts this functional relationship between stability and mobility can lead to dysfunction. Many of the stabilization strategies that encourage spinal bracing and a locking down of the thoracic spine actually lead to dysfunction. This is also a problem in individuals that extend through the thoracolumbar junction (T11 - L2) in an attempt to improve posture and adhere to the commands to “lift your chest up.”
How does this relate to groin and hamstring injuries? When individuals “lock down” their thoracic spine and rib cage (areas of mobility), they will compensate by moving through their lumbar spine and pelvis (areas of stability). Once the nervous system recognizes instability through the lumbar spine, there is reflexive up-regulation (increased activation) of the hamstrings and external hip rotators. This results in a subsequent loss of hip motion, leading to further movement dysfunction in the lumbar spine. Additionally, it leads to the femoral head being driven forward into the socket and the loss of internal hip rotation. Research has demonstrated that loss of internal hip rotation is a direct cause of anterior hip pain.
This is often complicated by weakness of the stabilizing structures of the femoral head in the acetabulum. Weakness of the gluteus maximus in hip extension and the iliacus/psoas complex in hip flexion has been shown to contribute to an increase in femoral head migration in the acetabulum and can therefore be considered a precursor to anterior groin injuries.
This change in pelvic alignment (posterior tilt and lumbar flexion) and femoral head position (anterior migration) then becomes a direct cause of hamstring injuries. The change in pelvis and hip alignment functionally inhibits the gluteus maximus, leading to synergist dominance of the hamstrings for hip extension. Because of their attachment to the ishcial tuberosity, the hamstring can not maintain an optimal axis of hip rotation. Along with the altered pelvic alignment, the hamstrings serve to drive the head of the femur further forward in the socket. Over time, the hamstrings fatigue from being overworked as hip extensors and become susceptible to tears and other overuse injuries.
Improving groin and hamstring injuries must address the fundamental principles governing neuromuscular function. They include establishing proper respiratory patterns, developing optimal stabilization and integrating the proper movement progressions.
- Proper respiratory patterns must be established. The diaphragm is a key component of the thoracic canister and therefore requires dynamic stabilization of the LPHC. Recall that the body will sacrifice posture, stabilization and optimal motion to fulfill its oxygen requirements.
- Optimal stabilization of the thoracic canister and LPHC is required prior to movement. If the first law is broken, dysfunctions in stabilization will soon follow. Research has repeatedly demonstrated feed-forward stabilization delays in individuals with low back, groin and knee injuries. Additionally, proper stabilization requires an ability to stabilize low level activities with a movement strategy (lighter activation) as well as a rigidity strategy (bracing type activation), which is better suited for higher level loading.
- The development of proper progressions must precede higher level or sport specific movement patterns. Too often, fundamental movement patterns are forsaken for the "sexier" sport specific or higher level training. Research into hamstring injuries in elite athletes demonstrated poor LPHC stabilization during single leg standing as one of the precursors to hamstring and groin injuries. Improving movement patterns will be required at all athletic levels to improve both the injured athlete as well as general conditioning in the non-injured athlete.
Therefore, improving function and decreasing the risk of groin and hamstring injuries includes:
- Improve diaphragmatic breathing patterns and stabilization of the LPHC and ThC
- Release of the posterior hips and re-establish neutral spine and femoral head positions
- Development of optimal functional movement patterns
While there are various approaches to teaching diaphragmatic breathing, the following is an easy method to begin with most of your clients. To ensure proper diaphragmatic movement, be sure there is three-dimensional movement in the thorax with minimal to no activity in the upper chest and neck throughout the movement.
- The client lies quietly on her back, the knees bent and supported, and takes a deep breathe in through the nose (observe the ribcage expanding front to back and side to side).
- The breath is held for five seconds at the top of the inhalation.
- The client then exhales through her mouth (relaxed lips) until all the air is out her lungs (the ribcage relaxes).
- This position is held for five seconds before inhaling again.
- Repeat for five to 10 cycles.
- Once the client perfects this, she will "activate" the abdominals following an exhale by gently creating tension in the lower abdominal region and through the lateral aspects of the trunk (area between the rib cage and pelvis). She must be able to maintain this tension while continuing to breathe diaphragmatically in order to maintain optimal trunk stabilization. This strategy is considered “true core stabilization.”
This should be performed a minimum of two to three times a day and also in the upright posture to ensure proper motor patterning. This is a powerful way to perform physiological quieting, restore diaphragmatic breathing and set clients up for core activation. They are then progressed to breathing with core activation and limb motion.
Posterior Hip Release
The next objective is to release the posterior hip structures. A stretching component is included for those trainers who stretch their clients. However, please note, stretching is always followed up with some form of muscle activation (isometrics, visualizations, palpation, etc.) to reconnect the system. The sequence includes releasing and stretching the posterior hips and then teaching the individual to reseat the femoral head in the socket.
Figure 1 (above): Hip Mobilization - Foam roll soft tissue release (a tennis ball can substitute). Roll each side holding over tonic areas.
Figure 2 (above): Hip Stretching - Activate the core and keep spine as neutral as possible. Hold for 15 seconds and repeat three times on each side. Use a bench or block for those individuals with less hip range of motion.
Hip Mobility (Femoral Head Placement)
Figures 3 and 4
Figures 3 and 4 (above): Quadruped Weight Shift - Activate core, keep spine neutral, and shift back. Repeat 20 reps in a slow controlled fashion. Make sure the movement comes from hip-pelvic dissociation and not lumbar spine flexion or from tilting the pelvis posteriorly. Maintain core activation and diaphragmatic breathing throughout the entire pattern.
Figure 5 (above): Progress to Squatting - Maintain core activation and spine neutral while allowing the hips to sit back. This “down and back” visualization aids repositioning of the hip in the socket.
Functional Movement Patterns
Once the individual is able to breathe optimally and establish core activation while moving effectively through the hips, more advanced patterns can be introduced. The one leg reach is a great way to teach single leg mechanics required for sport while teaching control of the anterior and posterior oblique chains. Perform 10 to 15 repetitions with short range reaches progressing to longer range reaches or loading the arm with dumbbells or cable resistance.
Figures 6 and 7 (above) - Client maintains core activation and diaphragmatic breathing as they shift onto one leg. The body must remain centered over the leg the hip must remain centered in the socket. The individual shifts through the hip and flexes the knee and ankle as they reach forward with contralateral arm. The spine and pelvis remain neutral as the individual returns to the upright position.
While groin and hamstring injuries are not 100 percent avoidable, the approach outlined within this article is effective at reducing the incidences because it addresses the fundamental causes of these injuries: dysfunctions in stabilization and movement. This approach can be instituted whether the athlete is taking part in a general conditioning program or has recently suffered an injury. Recall the key to avoiding and rehabbing these injuries:
- Identify the areas of dysfunction
- Restore stabilization and mobility to the appropriate region
- Progress through functional movement patterns to incorporate the LPHC and ThC into the kinetic chain
- Hungerford B, Gilleard W, Hodges P. Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain. Spine 28(14):1593ORT
- Lee LJ. Discover the Sports Pelvis: The Role of the Pelvis in Recurrent Groin, Knee, and Hamstring Pain & Injury, Course Handouts, Fairfax VA, 2008.
- Osar EM. Complete Hip and Lower Extremity Conditioning, Fitness Education Seminars, Chicago IL, 2005.
- Pirouzi S, Hides J, Richardson C, Darnell R, Toppenberg R. Low back pain patients demonstrate increased hip extensor muscle activity during standardized submaximal rotation efforts. Spine 2006 Dec 15;31 (26):E999-E1005.
- Sahrmann SA, Lewis CL, Moran DW. Anterior hip joint force increases with hip extension, decreased gluteal force, or decreased iliopsoas force. Journal of Biomechanics Aug 2007 40(16):3725-31.
- Verrall GM, Slavotinek JP, Barnes PG, Esterman A, Oakeshott RD, Spriggins AJ. Hip joint range of motion restriction precedes athletic chronic groin injury. Journal of Sports Science and Medicine 2007 Dec 10 (6): 463-6.