This is an excerpt from Dance Anatomy and Kinesiology 2nd Edition With Web Resource by Karen Clippinger.
Very large forces are generated and absorbed in the ankle - foot complex in dance. For example, ankle joint compression forces have been calculated to reach 5 times body weight during walking and 9 to 13 times body weight during running (Hamill and Knutzen, 2009). Considering these high forces and the complex structure and demands of the foot, it is not surprising that the ankle - foot complex is the site most frequently injured in dance. Studies listed in the references for this chapter on different forms of dance have found that the incidences of injury to the ankle - foot complex range from 27% to 49% of total injuries in ballet, modern, flamenco, and tap dancers (Garrick, 1999; Jacobs, Hincapie, and Cassidy, 2012; Mayers, Judelson, and Bronner, 2003; Salter-Pedersen and Wilmerding, 1998; Shah, Weiss, and Burchette, 2012; Solomon and Micheli, 1986), with female ballet dancers appearing to experience the highest incidence.
Prevention of Ankle and Foot Injuries
Considering the high incidence of injury involving the ankle and foot, prevention of injuries to this region should be a priority for dancers. Preventive conditioning measures include sound training principles to avoid excessive fatigue or abrupt increases in dance training by maintaining condition during layoffs or breaks, as well as performing supplemental strength, flexibility, and proprioceptive conditioning exercises. Preventive technique considerations include using appropriate placement of the body weight over the axis of the foot through various methods including use of the stirrup muscles and maintaining adequate turnout at the hip. With regard to equipment considerations, careful selection of well-fitting shoes, where appropriate (Walter, Docherty, and Schrader, 2011), well-designed transitions for the addition of pointe work in ballet dancers (Pearson and Whitaker, 2012), and use of floors with good resiliency and friction characteristics (Fiolkowski and Bauer, 1997; Hackney et al., 2011) whenever possible can also help prevent injuries to the ankle - foot complex.
Common Ankle and Foot Injuries in Dancers
A very brief description of selected injuries of the ankle - foot complex follows. Interested readers are referred to the authors cited in this section or related chapter references for a more detailed presentation of injuries. As in earlier chapters, these injury descriptions are not meant for self-diagnosis or treatment, and injured dancers are encouraged to seek diagnosis and treatment from qualified medical professionals.
The ankle sprain is one of the most common acute (traumatic) injuries seen in dancers. Although termed an ankle sprain, technically it involves injury to ligaments of both the ankle joint and the subtalar joint. About 85% of ankle sprains involve inversion (Whiting and Zernicke, 2008), and many involve plantar flexion such as in landing poorly from a jump or falling out of a turn. In the plantar-flexed positions of demi-pointe or pointe, the ankle joint is less stable and the anterior talofibular ligament (ATFL) is almost vertical and under tension such that an excessive inversion movement can readily produce injury (figure 6.40). Not surprisingly, the ATFL component of the lateral collateral ligament is the most commonly injured ankle - foot ligament in dancers and other populations (Hamilton, 1988; Martin et al., 2013).
In plantar flexion (right foot), (A) the anterior talofibular ligament (ATFL) is almost vertical and can be readily sprained with (B) inversion.
When the ankle is sprained, dancers often hear a pop or experience a tearing sensation with immediate pain. Swelling generally occurs around the ligaments (lateral malleolus); and if the sprain is sufficiently serious, the dancer feels that the ankle is unstable. Both passive inversion of the foot and ankle - foot plantar flexion tend to produce discomfort.
As to treatment, because this is a traumatic injury, PRICE (protection, rest [relative], ice, compression [as with an elastic ankle wrap], elevation) is particularly relevant, often for the first 48 to 72 hours (Russell, 2010). Protection might include taping, an air cast, or a functional walking orthosis.
As symptoms allow, rehabilitation often emphasizes strengthening the peroneals, such as with sitting little toes away (table 6.5E), and restoring the impaired response of the peroneals (Delahunt, Monaghan, and Caulfield, 2006) through the use of proprioceptive exercises.
Plantar fasciitis is an inflammation of the plantar fascia, often involving microtears in the fascia (Shea and Fields, 2002), that in rare cases can lead to rupture (Nielson and Micheli, 2004). Because of the key role the plantar fascia plays in supporting the longitudinal arch, this injury is commonly associated with jumping.
Plantar fasciitis is characterized by pain and tenderness on the underside of the heel (figure 6.41) where the plantar fascia attaches onto the calcaneus. A hallmark of the condition is morning stiffness. Some dancers complain that when taking the first few steps in the morning, they feel as though their feet are as stiff as boards.
Common site of pain with plantar fasciitis (left foot, posteromedial view).
Rehabilitation often focuses on stretching the plantar fascia (Covey and Mulder, 2013; Drake, Bittenbender, and Boyles, 2011) and strengthening the intrinsic muscles and extrinsic muscles that help support the longitudinal arch as with doming (table 6.5F) and sitting big toes away (table 6.5D). Control of excessive pronation and support of the medial longitudinal arch with taping or orthotic devices (Kuwada, 2011), as well as adding viscoelastic inserts or a heel cup to reduce shock, can also sometimes offer relief (Marshall, 1988).
The Achilles tendon is surrounded by a specialized sheath composed of fascia that is termed a paratendon. Inflammation and injury can occur to the paratendon, the tendon itself, or both. Achilles tendinopathy is a general term used to include both inflammation (tendinitis) and injury in and around the tendon (tendinosis). Although the Achilles tendon is the largest tendon in the body, it is not surprising that this tendon is commonly injured when one considers that this tendon has been estimated to bear forces 4 to 10 times body weight in running and jumping (Hamilton, 1988; Whiting and Zernicke, 2008).
Achilles tendinopathy is characterized by pain, tenderness, and swelling in and around the tendon (Maffulli, Longo, and Danaro, 2012), most commonly about .8 to 2.4 inches (2-6 centimeters) above its attachment onto the heel (figure 6.42) (Paavola et al., 2002). Dancers also often complain of a feeling of tightness and stiffness, particularly when awakening in the morning. Pain is generally reproduced or increased with active ankle - foot plantar flexion as in relevés or when the plantar flexors are working eccentrically and the tendon is dynamically stretched, as in the bottom of a plié.
Common site of pain and thickening with Achilles tendinopathy (left foot, lateral view).
Treatment is particularly challenging because healing and remodeling of the tendon are slow due to its poor blood supply. However, continuing to dance with Achilles tendinitis can lead to a chronic condition that involves scar formation and areas of tissue degeneration within the tendon itself (Chessin, 2012).
Wearing heel lifts (Macintyre and Joy, 2000) or viscoelastic heel inserts, Achilles taping, and control of excessive pronation (where indicated) can sometimes help reduce symptoms. When symptoms allow, loaded eccentric exercises for strengthening the triceps surae (Alfredson and Cook, 2007; Duerden and Keeling, 2008), such as calf raises performed while holding weights (table 6.5B) and with the lowering phase performed very slowly, are often included. There is evidence that eccentric training may help with desired remodeling of the fibers within the tendon, which is necessary for a strong and healthy tendon.
Posterior Ankle Impingement and the Os Trigonum Syndrome
Posterior ankle impingement occurs with extreme plantar flexion and can involve the compression of various structures between the back of the tibia and the calcaneus such as a bony process (Stieda's process) or an unfused small bone (figure 6.43) (Novella, 2004; Sainani et al., 2011). With regard to the latter, the back of the talus has a projection that normally fuses with the body of the talus between 9 and 12 years of age (Kadel, Micheli, and Solomon, 2000). However, in some cases this process fails to fuse and remains a separate little bone, termed an os trigonum, or separation of the os trigonum occurs due to trauma. When the os trigonum is the structure being impinged, this form of posterior ankle impingement syndrome is also termed os trigonum syndrome. Due to the extreme demands for plantar flexion, posterior ankle impingement syndrome occurs frequently in dancers and most frequently in female ballet dancers.
(A) Posterior ankle impingement risk increased by the presence of (B) an os trigonum or (C) a Stieda's process (right foot, lateral view).
With posterior ankle impingement syndrome, pain, tenderness, and sometimes swelling are generally experienced at the back of the ankle, deep to the Achilles tendon. This pain tends to be reproduced when the ankle-foot is brought into full plantar flexion, such as in tendu and particularly pointe work (Luk, Thordarson, and Charlton, 2013). A decreased range in plantar flexion is often present. Weakness and numbness may also be present.
Recommended initial treatment often includes limitation of ankle - foot plantar flexion in dance to pain-free limits and emphasis on use of the stirrup muscles to help achieve plantar flexion with potentially less compression. When symptoms allow, restoring plantar flexion range of motion and plantar flexor strength is often emphasized; but if conservative treatment fails, surgery may be recommended for professional and other serious dancers (Marotta and Micheli, 1992).
Shin Splints and Tibial Stress Syndrome
This text uses the term shin splints, also called tibial stress syndrome, to refer to activity-related pain and generalized tenderness on the anterior or medial shin (figure 6.44) that relates to injury of the tibia, the membrane covering the tibia (periosteum), or the surrounding musculature (Galbraith and Lavallee, 2009). While anterior shin pain was originally believed to involve the tibialis anterior and tibialis posterior muscles, there is evidence that the soleus (Hutchinson, Cahoon, and Atkins, 1998), flexor hallucis longus (Kortebein et al., 2000), or the bone itself (Yuksel et al., 2011) may also be responsible in some cases.
Pain associated with shin splints thought to reflect involvement of the (A) tibialis anterior and (B) tibialis posterior, flexor hallucis longus, or soleus.
Shin splints are evidenced by regular aching or long-lasting shin pain that is associated with activity such as dance. This shin pain is frequently accompanied by generalized tenderness along the anterolateral tibia (figure 6.44A) or the posteromedial tibia (figure 6.44B).
Since the muscles commonly involved in shin splints are invertors, rehabilitation often includes an emphasis on controlling foot pronation (Bandholm et al., 2008; Yates and White, 2004; Yuksel et al., 2011) with taping, arch supports, or orthotics (in street shoes), as well as strengthening the foot invertors as with sitting foot flex (table 6.5C) and sitting big toes away (table 6.5D). However, if despite conservative treatment the pain persists or becomes severe, it is important that the dancer see a physician to rule out more serious conditions such as a stress fracture.
Stress Fractures of the Lower Leg and Foot
As described in chapter 1, a stress fracture is a microfracture of a bone that often occurs in response to repetitive exercise stress when bone breakdown (resorption) temporarily outpaces bone formation (Moen et al., 2009) such that the bone is weakened. A stress fracture can occur in any of the bones of the lower leg or foot. In ballet dancers, the most common site for stress fracture is the metatarsals (Lundon, Melcher, and Bray, 1999), and the metatarsal most commonly affected is the second metatarsal (Harrington et al., 1993), as seen in figure 6.45.
Common site of stress fracture in dancers (right foot, superior view).
A stress fracture is generally associated with pain and tenderness that is localized to the site of the fracture and is initially aggravated by impact associated with movements such as jumps. However, if not heeded, the pain may become more severe, persistent, and easily initiated.
A cornerstone to successful treatment for a stress fracture is to temporarily unload the bone sufficiently - for example, with the use of a wooden shoe, brace, or crutches (Bolin, 2001; O'Malley et al., 1996) - to allow completion of the remodeling process so that the bone is stronger. In addition, adequate correction of risk factors including the female athlete triad (when indicated) is important not only to promote successful full return to dance but also to prevent recurrence (Kadel, 2006; Tenforde et al., 2013).
Rehabilitation of Ankle and Foot Injuries
As with injuries to other regions of the body, early recommended treatment usually uses ice, anti-inflammatory medications, and physical therapy modalities to reduce pain, increase range of motion, and promote healing while activity is modified so that it is pain free (Potts and Irrgang, 2001). Because of the load placed on the ankle and foot with weight bearing, more serious injuries may require an initial period of external support or nonweight bearing with an assistive device (Martin et al., 2013).
As symptoms allow, stretching and range of motion exercises are added in a pain-free range to help restore normal range of motion. Particular attention should be paid to stretching the triceps surae, since female ballet dancers tend to have diminished ankle - foot dorsiflexion range (Clippinger-Robertson, 1991; Hamilton et al., 1992), although not necessarily modern dancers (Dickson et al., 2012). Adequate range of dorsiflexion may help with absorption of large landing forces, avoidance of compensatory pronation, and prevention of double heel strikes during landing from jumps.
Again, as symptoms allow, strengthening exercises are added, often progressing from isolation exercises such as sitting point (table 6.5A) to more functional exercises such as calf raises with weights (table 6.5B), and later to proprioceptive exercises. Functional exercises are frequently initially performed where loading can be reduced, as in a swimming pool or on a Pilates reformer, and then gradually progressed to normal weight bearing. Similarly, while programs for some injuries may initially emphasize strengthening of a particular muscle group, programs are generally progressed to include balanced strengthening of key ankle - foot and other lower extremity muscles. Dance-specific movements that originally aggravated the condition are also gradually reintroduced, with particular care taken to correct any underlying technique problems such as excessive pronation, maintenance of turnout at the hip, or landing mechanics in jumps.
Proprioceptive exercises are very key in the rehabilitation process for the ankle-foot, as some injuries have been shown to impair reflex responses (Nawoczenski et al., 1985; Neumann, 2010) and subtle aspects of movement coordination that can interfere with full return to dance (Kiefer et al., 2013; Rein et al., 2011) and markedly increase the risk of injury recurrence. Proprioceptive exercises designed to challenge the ankle - foot complex often use relatively unstable surfaces such as wobble boards, foam rollers, or ankle discs (table 6.5G) with increasing challenges incorporated to promote quick neuromuscular responses such as adding relevés, closing the eyes, or catching weighted balls (Batson, 2009; Hutt and Redding, 2014; Liederbach, 2010).
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