Quadriceps (front thigh) strains occur from a variety of factors primarily postural position (pelvic alignment), poor soft tissue quality of the area, muscle extensibility, improper recovery, or imbalances between synergistic muscles. Previous thought was that if a muscle strains it is simply weak but as Shirley Sahrmann has pointed out, it could be also be due to poor synergistic muscle activity. In this case of a quad strain, the culprit it usually the rectus femoris. Since there are multiple muscles that can flex the hip (think: knee to chest action), one that is particularly active above 90 degrees of hip flexion is the psoas. Rarely do we see maximal sprints in soccer that allow for full hip flexion which can cause an imbalance of the anterior hip musculature. The rectus femoris is the only hip flexor that crosses the knee and hip joint. As a result, it’s put under significant eccentric stress during the lay back position (hip extension, knee flexion) before the ball is kicked (See 2nd picture)
R Hip Extension, R Knee Flexion
Besides the action of the kick and sprinting stride, pelvic position (altered core control), muscle tissue extensibility, and synergistic activity play a pivotal role.
Long in-seasons with short (or little) off-seasons lends itself to overuse issues at the pelvis. Mentioned above, the rectus femoris gets a ton of repetition due to the amount of yards covered in a game with minimal maximum hip flexion (psoas contribution). If the off-seasons are short, we try to hammer home the importance of proper pelvic positioning by using breathing techniques (PRI) to re-position the pelvis, reinforce proper rib positioning (exhalation), followed by reinforcing that position in the core stability drills we do. Since most of our soccer athletes live in gross-extension patterns, it makes sense to get them back to a more neutral pelvic position so that there can be optimal core and pelvic function.
With year long soccer becoming increasing popular, overuse tends to become the norm. Soft-tissue work is absolutely necessary in order to help maintain quality of the muscle and help it recover (seeing a manual therapist would be better). Everyone is the soccer community should invest in a 10$ roller that will last them years and only help prevent tissue injuries.
This is my favorite mobility drill for the rectus femoris (**do not due if it causes pain after a strain)
Synergistic Muscle Imbalance (Psoas>Rectus Femoris)
Mentioned earlier, the psoas is minimally active as a hip flexor when hip flexion does not reach above 90 degrees. As a result, it may be important to pick a few exercises to help bring the pendulum back to the middle in order to decrease the contribution of the other hip flexors.
Here are a few things to incorporate as part of the warm-up. 2×3 sets of 10-12 reps will be a good place to start. The progressions to use would follow this order….
Psoas Isoholds : longer holds with less reps –> 3 x 10sec holds/side
Dynamic Psoas Holds: more reps for shorter duration –> 8x2sec holds/side
Lying Miniband Psoas (knee must get above 90 degree without compensation at the spine)
Progression or Alternative: If the team does not have minibands, they could also use a hand to apply resistance downward