Even though an individual normally has the same ratio of slow/fast muscle fibres through out his or her body, the lower-limb muscles are predominantly designed to provide the maximum dynamic output in rapid movements (e.g. jumping). The limited data on dancers’ muscle profiles have shown that (ballet) dancers have predominately slow fibres. Muscular strength, together with aerobic and anaerobic capacity, joint mobility and muscle flexibility, and body composition form the continuum of physical fitness.
Strength is defined as the maximum force that a muscle group can generate at a specified velocity; its levels can be affected by several factors. which include age, gender, type of muscle fibre, nutrition, and body temperature. There is no scientific evidence suggesting that different strength training regimens should be employed for the different styles of dance. However, reduced muscular strength has been associated with greater severity of injury in dancers. Poor aerobic capabilities, high ectomorph ratings with low percent body fat values, and the biomechanics of different dance techniques have also been identified as underlying sources of injury in dancers. The most common location for injury in Irish dancers is the foot and the ankle. Many Irish dancers also experience knee and hip injuries too.
Muscular strength, along with aerobic and anaerobic capacity, power, joint mobility–muscle flexibility, body com-position, and body balance, mainly constitute what we under-stand as physical fitness. Without adequate physical fitness, we would not be able to perform and dance.
Muscular Strength Training for Irish Dancing
To our knowledge, there is no scientific evidence suggesting that different strength training regimens should be employed for the different styles of dance. However, exercise selection should be similar to the selection of warm-up activities and movements used during a dance performance.
General conditioning activities are initiated at the beginning of a yearly training schedule, much as general warm-up activities are utilized at the start of a movement preparation period. The main aim of strength training is to train the nervous system, not the muscle. By training the appropriate neural pathways, dancers will be able to activate a larger percentage of their musculature during a particular action. Muscle fibre hypertrophy normally comes much later. It should be noted that one month of detraining (i.e., inactivity) results in minimal muscle fibre atrophy and strength loss; after that, decreases in strength occur at a greater rate than decreases in fibre size. Prolonged inactivity normally represents a persistent catabolic stimulus that exacerbates strength and lean muscle loss via a chronic reduction in muscle protein synthesis.
Some misconceptions associated with strength training are that women will produce hypertrophic muscles. It is rather difficult for a woman to produce such muscles due to the fact that women generally have high levels of the hormone oestrogen, which, unlike the predominately male hormone testosterone, is not associated with muscle bulge. Strength improvements in women can be accomplished in muscle tone, strength, and endurance and not necessarily in size. Strength exercises also have been recommended as a means of preventing osteoporosis in dancers. This claim is supported by an earlier set of data on ballerinas, in whom bone density was found to be normal or elevated at weight-bearing sites whereas deficits were observed at non-weight-bearing sites.
A muscle will only strengthen when forced to operate beyond its customary intensity. This may be achieved by increasing:
2) the number of repetitions with a particular weight
3) the number of sets per exercise.
Beginner trainees are often introduced to bodyweight training, resistance training with bands, machines and/or simple free weights. Free weights can be utilized to more closely approximate certain dance movements, while the application of machines may allow isolating certain muscle groups for physical development and injury prevention. Apart from developing strength, the use of free weights or machines can lead to improvements of different fitness parameters.
A typical strength training program, already used in male and female dancers, lasts for approximately 12 weeks with up to three 50-min sessions/wk. using free weight exercises. During the first 2 weeks, exercises are of low resistance lifts(<70% of one-repetition maximum [1-RM]) but with high repetitions. The principle of high resistance (>75% of 1RM) with a low number of repetitions can be adopted for the remaining period during which resistance increases by about15 to 20%. A rest period of about 4 min was allowed between exercises in each test and between sets. Weak muscle groups need priority, more sets and exercises, whereas strong areas just require maintenance. The more difficult exercises should be performed when the dancer is fresh. During a strength training session, multiple-joint, large-muscle-mass exercises precede single-joint, small-muscle-mass exercises. Relatively heavy resistance that allows only slow movements should be part of strength training, as this may allow for more motor units to be recruited during the action.
Aerobic exercise and stretching should be performed first followed by resistance training participation. Dancers should demonstrate proper technique of each strength-exercise before participation is encouraged.
Muscular Strength and Injury Trends
With over 600 muscles, 206 bones, and countless ligaments and tendons in the body, it is almost impossible for dancers not to develop an injury (dance injury is defined here as the result of acute trauma or repetitive stress associated with dance activities). Acute injuries, such as muscle pulls, can happen at any time during a class, rehearsal, or stage performance. Chronic (or overuse) injuries, such as tendinitis, develop over longer periods of time. The nature of dance as a yearly activity should also be considered. Unlike athletes, dancers do not have predictable annual seasons during which a regular training schedule can be periodized to include regular resting periods following increased volumes of work. As a result, many dancers submit to problems such as over-training (or burnout), where their ability to adapt successfully to physical conditioning ceases. This may partly explain the high injury rates found in dance.
Therefore, a good understanding of anatomy and biomechanics is important for those working with dancers, and for dancers themselves.