Balance control is largely mediated by the interaction of the nervous system and the musculoskeletal system. Information for balance is obtained from visual, somatosensory, and vestibular systems to coordinate muscle action. Balance is a learned skill, and specific training has been shown to enhance it at all age levels.
Static balance is the ability to maintain a stable position of the COM relative to the base of support. While many tasks in functional activities are performed with the COM in motion, recovery of dynamic stability is still dependent on the ability to control the posture. Thus, dynamic and static stability are very much interrelated. Balance has been defined as the ability to maintain the body’s COM within some defined limits and is a complex coordination of reflexive and volitional movements in anticipation of and reactions to disturbances in stability. Balance performance limitations are often revealed in the extremes of task complexity and environmental challenge. An example of this is the noted increase in falls when older persons attempt to perform two tasks at once, such as talking while walking.
In order to understand our approach to balance training, it is important to understand the biomechanical principles that define balance. Postural stability is maintained by the body’s ability to control its center of mass (COM) over its base of support. This involves sensory detection of the COM position and motion, and subsequent integration of this information with the biomechanical constraints of the task and the environmental conditions. The most common method of COM control is by an ankle strategy, in which the shank is inclined to bring the body COM back to an appropriate position within the base of support. This is achieved through muscle action to produce moments at the joints. A hip strategy, reversing the relationship of the shank and thigh contributions, can also be used to counteract larger disturbances of balance. Failure to recover balance results in a fall.
An alternative approach is to specifically train balance and stability utilizing therapeutic interventions. This white paper will provide evidence supporting the use of one such intervention: balance training utilizing foot and ankle exercises. This concept has been supported by dynamic systems theory, which suggests that training distal points of the kinematic chain may have a greater impact on promoting behavioral changes.
Preventing falls and fall-related injuries among the elderly and others with compromised balance and stability is a pervasive and growing public health concern. Shoe and insole modifications or orthotics are often used to improve balance in persons with functional limitations. Several investigators have demonstrated improvements in static postural stability with the use of textured materials that provide some form of surface mechanical irritation. One limitation of this approach is that it artificially adds sensory input and may not specifically improve the use of the available somatosensory information for postural control. This may be particularly relevant in slippery environmental conditions where slipping of the textured material relative to the supporting surface can further challenge an individual’s balance.
Understanding Foot and Ankle Pain
Due to the significant reduction in gait efficiency caused by foot and ankle pain, balance and proprioceptive ability can be significantly impaired. Studies have shown that there is a strong relationship between the mechanoreceptors in the joints of the foot and ankle (more specifically the type 1b joint receptors and Ruffini endings) and balance and postural reactions. It is known that when joint pathology occurs in the foot and ankle, the muscle spindle activity and firing rate of the receptors associated with the afferent neurons in the muscle decrease significantly. This in turn leads to ataxic muscle activity and delayed functional response of the specific musculature. Joint receptors are shown to play a significant role in the spatiotemporal organization of a movement by providing necessary sensory feedback throughout the movement and adjustment of postural orientation to prevent any mechanical damage or energy waste. Therefore, decreased firing rate and activity of muscle and its associated joint receptor can lead to an increased risk of an acute or repetitive injury due to delayed muscle response and poor motor pattern coordination. Long-term changes in postural alignment, with a desire to reduce an increase in pain, can lead to early onset of osteoarthritis at certain joints.
Foot and ankle pain, more specifically improper functioning of the joints in the foot and ankle, can be the cause of significant debility and functional limitation. Among community-dwelling adults, the inability to stand on the toes and full weight bearing on a single leg for more than 10 seconds are essential tasks assessed in the physical examination that are both shown to be very difficult when foot and/or ankle pain is present. These tests are equated to not being able to walk ½ mile and climb stairs, and not being able to walk 2 blocks and perform activities with a moderate load. Chiropractic patients with chronic low back pain and unilateral plantar heel pain would have a substantial reduction in quantitative measures of standing rearfoot balance on the painful foot compared to a control. This shows that the general efficiency of movement is impeded when foot and ankle pain is present. With static and dynamic posture requiring maintenance or attainment of a position whereby the least amount of energy is used to do so, painful or inefficient feet will lead to changes in postural alignment in order to attain the same tasks.
Balance Training Exercises for Foot and Ankle Stability
Single Leg Stance Stand on one leg. Squeeze the leg muscles and maintain a neutral foot position with equal weight on the inside and outside of the foot. Hold this position for 30 seconds. Repeat 3 times on each leg.
Romberg Stance Stand with your feet together. Squeeze the leg muscles and maintain a neutral foot position with equal weight on the inside and outside of both feet. Hold this position for 30 seconds. Repeat 3 times.
Double Leg Stance Stand with your feet parallel and hip-width apart. Lift your toes to shift your weight to your heels. Squeeze the leg muscles and maintain a neutral foot position with equal weight on the inside and outside of both feet. Hold this position for 30 seconds. Repeat 3 times.
These exercises target the neuromuscular system, proprioceptive feedback, and the strength of the lower leg, thus improving the balance of the patient. The standard progression is from double leg to single leg stance exercises. To monitor progress, the patient should perform these exercises in front of a mirror, with the goal of keeping their hips level and not deviating from the frontal plane. If this occurs, then the patient is using their hip strategy rather than their ankle strategy to correct for sway, and they should regress to an easier exercise. All of these exercises are effective, and the clinician should use their best clinical judgment to determine which ones to use based on the patient’s functional level.
Tips for Preventing Falls and Injuries
Rearfoot stability has been shown to be crucial in preventing falls and the resulting injury. This is especially important in the elderly population. If you have experienced an ankle sprain of any severity, it is likely that you have impaired rearfoot stability. Try exercises such as picking up marbles with your toes or scrunching up a towel with your toes. These exercises can also be beneficial for those suffering toe extensor weakness or muscle weakness on the top of the foot. Ankle injuries can also lead to a decrease in strength of the peroneal muscles (muscles on the outside of the lower leg) which are very important in maintaining rearfoot stability. A study by Hertel, et al. showed that subjects with a history of ankle sprain had a slower onset time of the peroneal muscles after a sudden inversion movement of the ankle, signifying a deficit in ankle stability. Ankle inversion is the most common mechanism of ankle sprain. This study reinforces the importance of targeting the peroneal muscles in those with a history of ankle sprain to prevent re-sprain. An effective exercise for peroneal muscle strength is resistance band exercises moving the ankle into eversion and raising the foot up and in. This can be done without a resistance band just moving the foot and is often used in prevention of ankle sprain recurrence.
Incorporate balance exercises into your daily routine to enhance foot and ankle stability. Stand on one foot for 30 seconds while waiting in lines at the grocery store. Adopt a heel-toe walking pattern; this is less stable than the usual walking pattern and therefore challenges your balance and can improve lower extremity strength. Gently and slowly rise up on your toes, and then back down, to strengthen ankle muscles. Make sure you are near a wall or something you can hold onto for balance if you feel unstable. Perform each exercise twice. Balance exercises can have a high fall risk, so make sure you are near something stable to hold onto if you feel unsteady. In general, pointy-toed shoes should be avoided as they put the foot in a mechanically disadvantageous and less stable position.
