There is a growing body of research in strength and conditioning on injury prevention and post-training recovery, especially when it comes to the female athlete. There are many well-documented strategies for reducing injury specific to females such as neuromuscular or proprioception training, jump training, and the like (7,20,21). It is clear that for quality and efficient movement to occur, the athlete must possess adequate mobility, stability, and motor control (1,13,27,29). However, strength and conditioning professionals are becoming more and more interested in decreasing the likelihood of injury in female athletes using methods that extend past strengthening exercises. Research on self-myofascial release (SMR) shows the efficacy of using self-massage modalities to combat injury in the athletic population (1,14,16–18,25). Research on joint mobilizations performed by practitioners also prove to be efficacious in increasing joint range of motion (ROM), or restoring joint mechanics for proper biomechanics (11). However, these works have not addressed the widespread use of other self-care modalities like tennis balls, lacrosse balls, and resistance bands, or how these post-training recovery modalities may be useful to the female athlete. The modalities discussed in this paper may be implemented into a strength and conditioning program for female athletes of any level to improve performance and potentially decrease the likelihood of injury.
MANIFESTATION OF ASYMMETRIES, IMBALANCES, AND INJURY
The female athlete may sustain both chronic and/or acute injuries over the span of her athletic career. Acute injuries can be the result of player to player contact, poor playing surface, rotation about a planted foot, overuse, slips, falls, or many other possibilities (28). Many times, the ultimate cause of an acute injury can be influenced by chronic injuries and microtraumas. Injuries associated with long-term exercise and/or repetitive motions are often limited to the tendon (2). Common injuries in the female athletic population range from soft-tissue injuries, to ligamentous and fascial injuries.
Each sport tends to have specific movements that are performed in repetition, and over time these repetitious movements may lead to asymmetries and imbalances (29). There are unique motor control and biomechanical considerations for every athlete. Faulty motor control patterns or poor biomechanics must be addressed early in the strength and conditioning program. The resulting inflammatory response may lead to scar tissue in the fascia over time, which in turn may lead to muscular dysfunctions (14). When not properly addressed, these imbalances can manifest as overuse injuries, trigger points, scar tissue restrictions or fascial adhesions, and joint capsule restrictions.
Trigger points are hyperirritable areas associated within a taut band of a skeletal muscle that are painful during compression, contraction, or stretching of the muscles, and can elicit referred pain. A trigger point can manifest over time in musculature that is overworked, fatigued, tight, or weak (8,12,25). Because trigger points respond well to soft-tissue manipulation and massage therapy by improving viscoelastic properties of the muscle, it is reasonable that trigger points would respond in a similar way to self-care modalities that mimic manual massage therapy techniques (6).
Scar tissue restrictions and fascial adhesions are the result of injury, disease, inactivity, or inflammation (17,18). As the body goes through the phases of inflammation and tissue repair, the musculature and surrounding fascia can get stiff and sticky. This prevents the muscles from sliding and gliding normally, which inhibits motion, muscle length, normal function of the muscle tissue, and normal joint capsule mobility. In this situation, other muscles tend to overcompensate to make up for the muscles that are no longer functioning properly. When scar tissue adhesions have formed, self-care modalities can be used to help restore the sliding surface properties to the skin, underlying tissue, or bone.
Capsular tightness is a biomechanical problem that manifests in inhibited motion or pain (5). Over time, the connective tissue of the joint capsule can lose the ability to lengthen, leading to impaired gliding surfaces and subsequent joint stiffness (4). Achieving proper ROM can be difficult for a female athlete who is already experiencing tightness or weakness. Compensatory actions can often be located above or below the joint that has limited joint ROM (20). Passive joint mobilization is commonly used by physical therapists to reduce pain and increase function to restrictions involving decreased ROM in joints like the shoulder, ankle, and knee (10,21).
Traditionally, the most common modality used for self-care has been the foam roll. Research states that foam rolling can help correct muscular imbalances, alleviate muscle soreness, relieve joint stress, improve neuromuscular efficiency, improve joint range of motion, and correct soft-tissue restrictions. Additionally, foam rolling has been linked to recovery benefits like decreases in pain and inflammation and increases in blood flow to musculotendinous structures (14,17,18). Physical therapist practitioners use myofascial release (MFR) manual therapy to reduce restrictive barriers. However, SMR gives the athlete the opportunity to perform these same types of MFR techniques without the help of a practitioner. SMR can be considered much more functional than traditional flexibility training, especially when it is necessary for the athlete to achieve dynamic movements uninhibited by joint restrictions (1,4,6).
A lacrosse or tennis ball is simply just another implement used to mimic the same effects of SMR with a foam roll. However, due to the small and compact nature of the ball, it can provide massage and direct pressure to deeper myofascial structures, which a foam roller cannot. A softball can be used for areas such as the hamstring that require a slightly larger, and less pointed implement than a lacrosse ball.
A “tack and slide” method can be used to enhance the function of the lacrosse ball by ungluing fascia and scar tissue adhesions. This method works by causing friction between the myofascial structures and promoting a shearing effect between the tissues that are affected by adhesions. It can be used to more aggressively massage tissues that are stiff, and restore range of motion to joints that are immobile. To employ this method, the athlete uses a lacrosse ball to place direct pressure on the inflamed tissue to “tack” down the tissues, sandwiching them together. Next, the athlete moves the limb or body part through the desired normal range of motion, while maintaining pressure on the inflamed tissue to slide the muscle belly through the fascial sheath in an attempt to break the myofascial tissue free of adhesions. In this way, the “tack and slide” method helps to correct soft-tissue restrictions.
Joint mobilizations are another self-care modality that are normally performed on an athlete by a practitioner. However, by using a heavy resistance band, the athlete is allowed to perform self-joint mobilizations, creating either compression or traction of a joint. For a self-joint mobilization aimed at joint distraction, the band pulls in the opposite direction of the limb or body, thereby creating distance between the articular surfaces of the joint, thereby improving joint ROM (11). Compression of a joint can also be achieved with self-joint mobilization by using the band to pull the articular surfaces closer together so as to initiate improved biomechanical positioning and clearing impingement of any surrounding tissues.
Lastly, proprioceptive neuromuscular facilitation (PNF) stretching techniques are used in combination with all of the aforementioned modalities. PNF can help restore function to the muscle belly itself, not necessarily to the tendinous or ligamentous tissue. With contract-relax PNF, the athlete contracts the muscle experiencing a limited ROM and then immediately relaxes it so that the muscle reaches a more lengthened position (9,11).
IMPLEMENTATION OF A PROPOSED INJURY PREVENTION PROGRAM
To assess the effectiveness of a specific modality or see any marked acute change in the athlete's mobility, a coach must test the athlete before the modality is used, and after. For acute tissue change to take place, it is suggested that a bout of 1–2 minutes is performed for each self-care modality (8,17,18). This prescription allows ample time for the tissue to change under compression, pressure, or friction.
It is extremely important that the athlete is not in pain during any of these modalities. Female athletes who are currently injured or experience pain with any of these movements should discontinue until under the supervision of a healthcare professional. Other types of injury prevention programs require the athlete to perform corrective training strategies such as neuromuscular training during off-season, or just before the season, whereas self-care modalities can be programmed during any part of the competitive and training season.
Some coaches may wish to use self-care modalities as part of a warm-up to initiate proper functioning of the musculature and connective tissue. Another option is to use these modalities as an inter-set rest or active recovery in between exercises during the workout. This can be especially useful when a modality is paired with a similar movement pattern. For example, during the push press, the athlete does a 2-minute bout on an overhead banded distraction to clear impingement of the humeral head, then proceeds to immediately initiate an overhead exercise such as the push press. Lastly, these modalities can be used as a cool down or post workout/competition routine to accentuate tissue recovery. During this time, each female athlete focuses on movements specific to her own needs.
As athletes learn the proper technique for self-care modalities, they can also assist one another. With coaches who face demanding schedules, having the athletes educate new teammates can be an invaluable time-saving and team-bonding strategy.
PROGRAMMING CONSIDERATIONS FOR THE FEMALE ATHLETE
Female athletes have unique training needs and considerations different than that of male athletes. Strength and conditioning programs for women must account for a multitude of factors. Specific to injury prevention, 2 factors will be addressed in this paper–hormonal differences and training age.
One of the largest differences between men and women in sport is the female hormonal cycle. The menstrual phase is comprised of 3 phases, the follicular phase (days 1–9), ovulation phase (days 10–14), and the luteal phase (days 15 to the end of the cycle). Estrogen surges during the ovulation phase and progesterone levels rise during the luteal phase. Although it is less known what role progesterone specifically plays, it is well documented that estrogen affects the strength of fascia and connective tissue, muscle function, and functioning of the central nervous system (15,30,31).
It has long been hypothesized that it is because of these hormones that female athletes have a higher propensity for anterior cruciate ligament (ACL) injuries than their male counterparts. ACL ruptures are common, especially for ground-based women's sports like gymnastics, soccer, and basketball. There are many factors that contribute to this specific injury and these factors have yet to be determined as to which one is the leading cause, especially when there are so many intrinsic and extrinsic variables (22–24). Specific to ACL injuries, researchers have reported that women in their studies tended to have a significantly greater percentage of injury during the ovulatory phase and fewer injuries than expected during the luteal phase (30,31). In several reviews of literature on the properties of the patellar tendon with respect to fluctuating hormone levels, it has been reported that there is a significant effect on knee laxity. These findings link estrogen to having more of a chronic impact on the state of tendon tissue, rather than an acute impact. This research may suggest that these hormones can have a profound effect on all tissues and joints in the body during the ovulation phase, not just that of the knee. As a result, the menstrual phase does not necessarily need to be considered as a risk when creating a strength and conditioning plan (3). However, it still stands to reason that special care can be taken when dealing with a population who is more at risk when compared with male populations. As a precaution, the coach should encourage the female athlete to emphasize using modified SMR and joint mobilization techniques at all times, regardless of time of menstrual cycle.
When Title IX was passed, all federally funded programs in schools were required to provide equal opportunities to female athletes. However, that does not mean that disparities between genders have disappeared when it comes to sport. Female athletes are typically not introduced to strength training until a later age, when compared with male counterparts who may start weight training in private sports enhancement facilities during grade school or junior high. Once athletes are at high school level play, male athletes are more likely to have the required training by coaches, participate in annual strength training programs, and train more frequently (26). Unlike male athletes who may already have an established level of strength and motor control by high school, females tend to have lower levels of strength, especially in the upper body. Research on youth boys and girls displays marked differences in athleticism that exist with regard to explosive strength of the upper and lower body (19). Basic levels of strength and neuromuscular control must be established first before any advanced training is introduced to the female athlete.
Strength and conditioning coaches often have limited time, so using this time to establish basic levels is crucial. Time in the gym is spent lifting weights, or performing plyometric and conditioning drills. As a result, recovery is simply not an emphasized facet to the weight room programming. Until recently, female athletes have not always received the same quality resources as males. Another discrepancy between men's and women's sports is that coaches of female athletes are less likely to use certified coaches to plan and implement their strength and conditioning programs, and more likely to use volunteer coaches or interns as staff (26). Women's programs have been known to have costs cut by having to use subpar facilities. Women's team sports sometimes must also resort to competing on artificial turf or using older equipment and facilities that could potentially pose an injury risk for those participants.
LOWER BODY MODALITIES
PSOAS—LACROSSE BALL OR SOFTBALL
In a prone position, the athlete places the lacrosse ball 2 inches from the umbilicus and 1 inch down toward the anterior superior iliac spine. The athlete can palpate or roll the ball around to find tight spots. Another strategy is to use a PNF contract-relax sequence to facilitate myofascial stretch. Each time the athlete contracts and subsequently relaxes, the ball will place more and more pressure on the psoas as she sinks deeper into the ball. For the tack and slide alternative, the athlete flexes the knee to 90° (Figure 1). Once in this position, the contraction of the hamstring allows the quadriceps to relax enough to let the ball sink into the tissue, tacking down the psoas to the ball. The athlete then extends and flexes the knee slowly (without contracting the abdominals), to slide the soft-tissue structures back and forth. The flexed knee can be swept from side to side in a windshield wiper fashion to promote sliding as well.
EXTERNAL ROTATORS/TENSOR FASCIAE LATAE—LACROSSE BALL
The athlete is made to sit upright with one glute on the lacrosse ball. The athlete finds the tight or tender tissue, then holds that position so as to let the weight of the body sink into the ball. PNF contract-relax may be used for very tender areas. For the tack and slide method, the athlete will tack down the tissue by exerting pressure against the ball, then proceed to slowly drop the knee to the floor and back in towards the midline to create a sliding effect.
HAMSTRING—LACROSSE BALL OR SOFTBALL
Have the athlete sit on a plyometric box so that her knees are at 90° when seated. Place a lacrosse or softball underneath one hamstring. Have the athlete roll, while maintaining good posture, working up and down the length of the hamstring, and back and forth to the medial and lateral borders. When an especially tender spot is found, perform a PNF contract-relax sequence. As an alternative, have the athlete place both hands on the top of the quadriceps to tack down the hamstrings against the ball. Next, lift the lower leg into knee extension and lowering back down to create a sliding effect.
While sitting on a plyometric box, the athlete crosses one ankle over the opposite knee. Using a lacrosse ball, follow the anatomical seam and create a separation of the gastrocnemius and soleus muscle tissue from the tibia. To tack and slide, create pressure on the ball with the hands, then dorsiflex and plantar flex the foot.
PSOAS/EXTERNAL ROTATORS/GLUTE—SELF-JOINT MOBILIZATION—RESISTANCE BAND
Lateral hip distraction
The lateral hip self-mobilization requires the band to be affixed to an immovable object at shin level. Have the athlete place the band at the inside of the groin. Walk or step laterally from the mounting system to create the desired amount of tension on the band. Instruct the athlete to sink down into a lunge position, this time with the nonbanded knee on the ground (Figure 2). To accentuate the mobilization, the athlete may use several PNF contract-relax techniques to oscillate deeper and deeper into the position. Contract against the band for 6 seconds, then relax and push the torso deeper to the ground. The athlete should also try to push her knee to the outside of her foot to encourage external rotation of the hip in a flexed position.
Hip flexor I
Affix a heavy resistance band to an immovable object at shin level. Have the athlete slip one leg through the band while placing it on the front of the upper quadriceps at the bend in the hips, then walk or step forward to create the desired amount of tension on the band. Instruct the athlete to sink down into a lunge position, with the banded knee on the ground. The athlete's posture should remain completely upright with erect posture (not leaned forward), with the front hip locked out in full extension. To accentuate the mobilization, the athlete may use several PNF contract-relax techniques to oscillate deeper and deeper into the position.
Hip flexor II
For the second hip flexor self-mobilization, affix the band to an immovable object at shin level. Have the athlete assume the same position with the band at the hip crease, then walk or step forward to create the desired amount of tension on the band. Instruct the athlete to sink down into a lunge position, this time with the nonbanded knee on the ground. To accentuate the mobilization, the athlete may use several PNF contract-relax techniques to oscillate deeper and deeper into the position. The athlete can move into a lower position on this distraction. Have the athlete place one hand on the outside of the forward foot. Instruct her to push the knee out down, and over the toes to achieve full ROM in the flexed position.
BILATERAL SQUAT SELF-MOBILIZATION—RESISTANCE BAND
The deep squat self-mobilization requires the band to be affixed to an immovable object at shin level.
The athlete steps through the band with both feet and places the band around the mid glute, placing the feet slightly wider than hip width, with toes pointed forward. Using the 2 sides of the band in front as handles, the athlete should passively sit down into the deepest position she can get into. The hamstrings should be resting on the calf. While in this lowered position, the athlete can slowly oscillate from side to side, pushing the knee to the outside of each foot, without lifting either heel. The athlete can also use the upper body to pull against the band to lift the torso and head into a more upright posture (Figure 3).
ANKLE SELF-MOBILIZATION—RESISTANCE BAND
To mobilize restrictions in the anterior aspect of the ankle, have the athlete slip one foot through the band while in a standing position so that the band is on the front of the ankle. Stretch the band forward to reach the desired amount of tension. Keep the entire foot planted and allow the band to pull the tibia and fibula backward. To accentuate the mobilization, push the knee towards the ground without lifting the heel. Do not allow the ankle to rotate internally, or the arch to drop.
To mobilize restrictions in the posterior aspect of the ankle, have the athlete slip one foot through the band while in a standing position so the band is on the back of the ankle. Stretch the band backward to reach the desired amount of tension. Keep the entire foot planted and allow the band to pull the tibia and fibula forward. To accentuate the mobilization, push the knee toward the ground without lifting the heel (Figure 4). Do not allow the ankle to rotate internally, or the arch to drop.
UPPER BODY MODALITIES
T-SPINE—DOUBLE LACROSSE BALL
Have the athlete assume a supine position and place 2 lacrosse balls (taped together) below the cervical spine. The athlete can lie completely on her back with her arms at her side or overhead. Vertebrae by vertebrae, the athlete will move the lacrosse balls down the thoracic spine. Once a trigger point is found, the tack and slide alternative can be used, by slowly bringing both arms overhead in the sagittal plane and back down to the side several times. A more aggressive release requires the athlete to leave the arms at the sides of the body and lift into a hip bridge by fully extending the hips toward the ceiling, pressing the lacrosse balls deeper into the myofascial tissue.
LATISSIMUS DORSI—LACROSSE BALL
Have the athlete assume a prone position and place the double lacrosse ball stacked vertically at the base of the armpit, feeling around for tender tissue near the humeral head (Figure 5). With the other arm, she may prop her head up to support the neck. Once the correct position is found, the tack and slide may be used by allowing the weight of the body to tack down the tissue, and then raising the arm slowly into shoulder flexion to initiate the sliding properties.
PECTORALIS MINOR—SOFTBALL OR LACROSSE BALL
While assuming a prone position, the athlete places a single lacrosse ball, double lacrosse ball or a softball on the outer pec, feeling around for tender tissue from the sternoclavicular joint, down to the lateral edge of the pectoralis group. Once a tight spot is found, the PNF contract-relax technique may be used, allowing the weight of the athlete to compress the musculature against the ball with each relaxation.
TRAPEZIUS/ROTATOR CUFF—LACROSSE BALL
The athlete has 3 locations to find with this release technique; (a) the top of the scapula on the upper trapezius, (b) the lateral edge of the scapula, and (c) between the medial border of the scapula and the spine. While laying supine, the athlete starts by placing the lacrosse ball at the top of the right scapula and works in a clockwise fashion, (or counterclockwise for the left scapula) until all positions are reached. The athlete should roll on the ball to find tender spots. The tack and slide method can be used with the weight of the body tacking down the tissue, then moving the arm overhead to initiate the sliding component. When mobilizing the right shoulder, the athlete will start with the thumb of her right hand near her hip or left pocket. Next, she slowly brings the arm up overhead to the right side while opening the palm. This movement will mimic the D2 Flexion PNF pattern. The pattern can be repeated several times and can be used in all 3 locations around the scapula.
GLENOHUMERAL JOINT—SELF-MOBILIZATION—RESISTANCE BAND
The shoulder flexion position mimics that of a front rack position in the clean and jerk. It will require the band to be affixed to an immovable object at shin or knee level. Start by having the athlete hook her wrist through the end of the band instead of simply grabbing it. Place the arm into external rotation before stepping under and bringing the hand and arm behind the body. The elbow should be pointed toward the ceiling and the palm should still be facing up (Figure 6). Shifting the weight slightly forward can accentuate the self-mobilization.
The overhead banded self-mobilization requires the band to be affixed overhead to an immovable object. Start by having the athlete hook her wrist through the end of the band instead of simply grabbing it. Place the arm into external rotation by holding it with the opposite hand before folding at the hips and sinking down (Figure 7). To perform a PNF contract-relax sequence in this position, have the athlete contract against the resistance band to draw the scapula down and back and then relax to increase the mobilization.
Understanding the risk of injury in the female athlete is very important for those delivering strength and conditioning programs. To develop programs to combat the growing concern of athletic-related injury events, they must include all necessary aspects of performance enhancement, including recovery through self-care modalities.
There are a multitude of tools for injury prevention. Figure out what works best for each unique programming need. By applying specific modalities at each joint as needed, improving joint ROM and decreasing tissue restrictions, the athlete will begin to use more efficient movement patterns. This in turn can decrease the likelihood of injury and enhance performance (24).
Although establishing a base of strength, speed, and neuromuscular control is important for the female athlete, it is equally important to program and encourage self-care modalities. In doing so, female athletes have the opportunity to use these injury prevention strategies to be successful throughout her athletic career and life.
1. Brooks T, Cressey E. Mobility training for the young athlete. Strength Cond J 35: 27–33, 2013.
2. Buchanan C, Marsh R. Review: Effects of exercise on the biomechanical, biochemical and structural properties of tendons. Comp Biochem Phys Part A 133: 1101–1107, 2002.
3. Burgess K, Pearson S, Onambele G. Patellar tendon properties with fluctuating menstrual cycle hormones. J Strength Cond Res 24: 2088–2095, 2010.
4. Conroy D, Hayes K. The effect of joint mobilization as a component of comprehensive treatment for primary shoulder impingement syndrome. J Ortho Sports Phys Ther 28: 3–14, 1998.
5. Cosby N, Grindstaff T. Restricted ankle dorsiflexion self-mobilization. Strength Cond J 34: 58–60, 2012.
6. Dolder P, Roberts D. A trial into the effectiveness of soft tissue massage in the treatment of shoulder pain. Aust J Phys 49: 183–188, 2003.
7. Fischer D. Neuromuscular training to prevent anterior cruciate ligament injury in the female athlete. Strength Cond J 28: 44–54, 2006.
8. Fryer G, Hodgson L. The effect of manual pressure release on myofascial trigger points in the upper trapezius muscle. J Bod Mov Ther 9: 248–255, 2005.
9. Godges J, Mattson-Bell M, Thorpe D, Shah D. The immediate effects of soft tissue mobilization with proprioceptive neuromuscular facilitation on glenohumeral external rotation and overhead reach. J Ortho Sports Phys Ther 33: 713–718, 2003.
10. Green T, Refshauge K, Crosbie J, Adams R. A randomized controlled trial of a passive accessory joint mobilization on acute ankle inversion sprains. Phys Ther 81: 984–994, 2001.
11. Hanten W, Chandler S. Effects of myofascial release leg pull and sagittal plane isometric contract-relax techniques on passive straight-leg raise angle. J Ortho Sports Phys Ther 20: 138–144, 1998.
12. Hanten W, Olson S, Butts N, Nowicki A. Effectiveness of a home program of ischemic pressure followed by a sustained stretch for treatment of myofascial trigger points. Phys Ther 80: 997–1003, 2000.
13. Hauschildt M, McQueen B, Stanford G. The core mobility series: A dynamic warm-up
tool. Strength Cond J 36: 81–87, 2014.
14. Healey K, Hatfield D, Blanpied P, Dorfman L, Riebe D. The effects of myofascial release with foam rolling on performance. J Strength Cond Res 28: 61–68, 2013.
15. Hewett T, Zazulak B, Myer G. Effects of menstrual cycle on anterior cruciate ligament injury risk. Am J Sports Med 35: 659–668, 2007.
16. Huang S, DiSanto M, Wadden K, Cappa D, Alkanani T, Behm D. Short duration massage at the hamstrings musculotendinous junction induces greater range of motion. J Strength Cond Res 24: 1917–1924, 2010.
17. MacDonald G, Button D, Drinkwater E, Behm D. Foam rolling as a recovery tool after an intense bout of physical activity. Med Sci Sports Exerc 46: 131–142, 2014.
18. MacDonald G, Penney M, Mullaley M, Cuconato A, Drake C, Behm D, Button D. An acute bout of self-myofascial release increases range of motion without a subsequent decrease in muscle activation or force. J Strength Cond Res 27: 812–821, 2013.
19. Marta C, Marinho D, Barbosa T, Izquierdo M, Merques M. Physical fitness differences between prepubescent boys and girls. J Strength Cond Res 26: 1756–1766, 2012.
20. Moreside J, McGill S. Hip joint range of motion improvements using three different interventions. J Strength Cond Res 26: 1265–1273, 2012.
21. Moss P, Sluka K, Wright A. The initial effects of knee mobilization on osteoarthritic hyperalgesia. Man Ther 12: 109–118, 2007.
22. Myer G, Brent J, Ford K, Hewett T. Real-time assessment and neuromuscular training feedback techniques to prevent anterior cruciate ligament injury in female athletes. Strength Cond J 33: 21–35, 2011.
23. Noyes F, Barber-Westin S, Tutalo Smith S, Campbell T. A training program to improve neuromuscular and performance indices in female high school soccer players. J Strength Cond Res 27: 340–351, 2013.
24. Pettino S, Jestes K, Lehr M. Female ACL injury prevention with a functional integration exercise model. Strength Cond J 26: 28–33, 2004.
25. Renen-Ordine R, Alburquerque-Sendin F, De Souza D, Cleland J, De Las Penas C. Effectiveness of myofascial trigger point manual therapy combined with a self stretching protocol for the management of plantar heel pain: A randomized controlled trial. J Ortho Sports Phys Ther 41: 43–50, 2011.
26. Reynolds M, Ransdell L, Lucas S, Petlichkoff L, Gao Y. An examination of current practices and gender differences in strength and conditioning in a sample of varsity high school athletic programs. J Strength Cond Res 26: 174–183, 2012.
27. Stodden D, Brooks T. Promoting musculoskeletal fitness in youth: Performance and health implications from a developmental perspective. Strength Cond J 35: 54–62, 2013.
28. Tolbert T, McIlvain G, Giangarra C, Binkley H. Injury rates in high school and collegiate athletics. Strength Cond J 33: 82–87, 2011.
29. Wheeler R. Developing mobility and stability in the high school environment. Strength Cond J 31: 23–26, 2009.
30. Wojtys E, Huston L, Boynton M, Spindler K, Lindenfeld T. The effect of the menstrual cycle on anterior cruciate ligament injuries in women as determined by hormone levels. Am J Sports Med 30: 182–188, 2002.
31. Wojtys E, Huston L, Lindenfeld T, Hewett T, Greenfield ML. Association between the menstrual cycle and anterior cruciate ligament injuries in female athletes. Am J Sports Med 26: 614–619, 1998.