PT on the Net Research

Scientific Balance Training - Part 1


I’m not going to lie to you. This is a technical series of articles that will challenge many readers for a variety of reasons. Some may be challenged by the anatomy, some may be challenged by the concepts and others may find the realities of balance training and how it relates to fitness professionals a bit alarming. The goal was not just to write an article on balance training and show the reader a few of exercises they could do with their clients. Rather, we were interested in showing you the science behind balance training and to provide a structural approach.

Today’s population is more unhealthy than ever before in history, including a large number of people suffering from a variety of orthopedic dysfunctions. How does this relate to you? Many of these people are your clients, and if you don’t have a solid grasp of what you are doing when prescribing exercises to them, you may be doing far more harm to them than good!

When reading this article, we recommend you spend some time going through it more than once. A good anatomy textbook and a highlighter may prove to be valuable in later parts of this article especially. More than anything, we want to show you that balance training is not as simple as some make it out to be and that there is much more to balance training than meets the eye. Our hope is that this article series will provide you with the tools necessary to start prescribing smart exercise programs and helping your clients far beyond their expectations!

Introduction

Balance training is needed today more than ever! It is projected that by the year 2045, there will be 77 million people older than the age of 65, and one out of every five people will be age 85 or older! Almost half the population over age 74 has difficulty with common functional activities, such as lifting, climbing stairs, walking, standing, bending, reaching and grasping, and it is well known that the most common orthopedic injury among the elderly are hip fractures.

To address the growing numbers of elderly members joining gyms and health clubs, emphasis will need to be placed on exercises that improve key biomotor abilities such as strength, endurance, balance, agility, coordination and flexibility. Accomplishing these objectives requires greater emphasis on functional exercise programs, including Tai Chi, Yoga, Swiss ball training and free weight training, and a greater emphasis will need to be put on the skillful use of tools such as the Fitter, balance boards and BOSU balls. Notice I said skillful use of balance tools...  that will be part of my focus in this article series.

Tai Chi has been shown to positively augment physical therapy programs aimed at improving balance, posture, coordination and integration of movement, endurance, strength, flexibility and relaxation. Swiss ball training has been shown to improve balance in a controlled study and has been used as a key modality in the treatment of neurologically impaired patients for over 30 years. Effective implementation of these functional exercise programs will require a more structured approach to balance training than is currently being used, and it will require that gyms provide the space for these types of exercise, particularly in the free weight area.

The topic of balance training is exceedingly complex. Though much more could be written on the subject than I am including here, it is my intention to give the reader a better understanding of the science behind balance training and to show you it’s not quite as easy as simply putting someone on a balance board or foam roller. That being said, here are the objectives for this series of balance training articles:

We will be covering the first of these objectives in this part of the series.

HOW STABILITY AND POSTURE RELATE TO BALANCE

While the terms stability and posture may appear to be two distinct terms at first glance, they are intimately related to one another - especially with regard to balance and the related functional applications of such training.

SEGMENTAL STABILITY

The ability for any joint complex in the human body to function without internal derangement during normal human activities requires the maintenance of an Optimal Instantaneous Axis of Rotation (OIAR). While there a variety of joint types in the human body, joint movement can be broken down into the following: surface gliding, linear gliding, rocking or rolling motion, rocking combined with gliding motions and/or axial rotation. All joints in the human body are under the influence of segmental stabilizers (muscles crossing that joint only) and gross stabilizers (muscles crossing multiple joints). For example, the shoulder joint receives segmental stability from the rotator cuff musculature, while larger muscles like the pectoralis major and latissimus dorsi serve as gross stabilizers. Assisting with joint stabilization are ligaments, joint capsules and fascial structures such as the iliotibial band.

Every joint complex in the body is richly innervated with mechanoreceptors or nerve endings highly sensitive to motion that provide information regarding joint position, pressure, tension and pain (Table 1). When the active and passive systems of the body effectively stabilize a given joint and maintain an OIAR, normal neuromechanical relationships allow pain free function.

Figure 1. Segmental Stability
  1. Maintenance of an optimal instantaneous axis of rotation (OIAR) results in physiological mechanoreceptor response and joint health.
  2. Loss of an OIAR results in capsule and ligament stress, strain and/or injury. Due to mechanoreceptor influences on tonic and phasic musculature, locally and globally, faulty recruitment patterns may disrupt recruitment of gross stabilizers and balance!

However, in the presence of a muscle imbalance or faulty recruitment of stabilizer muscles, the chances of maintaining segmental stability and an OIAR are significantly diminished. This will likely result in aberrant strain in the capsular and ligamentous structures of the joint complex and may cause faulty proprioceptive information to be sent to the spinal cord and brain (Figure 1-B). Additionally, there will be compensatory facilitation of key muscles around the involved joint complex and possibly other areas of the body.

Because the Type I mechanoreceptors are located in the most superficial portions of a joint capsule, they are the first to be damaged any time there is of a loss of an OIAR that induces non-physiological loading of the joint capsule and ligaments. If the joint structure is damaged enough to traumatize the deeper fibers of the capsule, there will also be destruction of Type II mechanoreceptors.

TABLE 1. Joint Mechanoreceptors
JOINT RECEPTORS FUNCTION
Type I Low threshold, slowly adapting static and dynamic mechanoreceptors. Tonic reflexogenic effects on neck, limb, jaw and eye muscles. Postural and kinesthetic sensation. Pain suppression. Facilitate the tonic muscle system.
Type II Fast adapting, low threshold dynamic mechanoreceptors. Phasic reflexogenic effects on the neck, limb, jaw, and eye muscles as well as pain suppression. Facilitate the phasic muscle system.
Type III High threshold, very slow adapting receptors. Have the same characteristics as a golgi tendon organ.
Type IV High threshold, non-adapting pain provoking nerve fibers. These fibers have tonic reflexogenic effects on the neck, limb, jaw and eye muscles. They also induce cardiovascular reflexogenic effects. Facilitation can cause guarding in the tonic muscle system.

Another important aspect to understand is that the Type I mechanoreceptors communicate directly with the tonic muscles of the body and the Type II mechanoreceptors communicate with the phasic muscles of the body. For a better understanding of tonic and phasic muscles, please refer to Table 2.

Table 2. Properties of Tonic and Phasic Musculature
Modified from (7) and (8).
Predominantly Tonic Muscles Predominantly Phasic Muscles
Prone to Hyperactivity Prone to Inhibition
Function
Posture Movement
Susceptibility to Fatigue
Late Early
Reaction to Faulty Loading
Shortening Weakening

Shoulder Girdle - Arm

  • Pectoralis Major & Minor
  • Levator Scapulae
  • Trapezius (upper)
  • Biceps Brachii
  • Scalenes
  • Subscapularis
  • Sternocleidomastoids
  • Masticatory
  • Forearm Flexors
  • Rhomboids
  • Trapezius (middle)
  • Trapezius (lower)
  • Triceps Brachii
  • Deep Neck Flexors
  • Forearm Extensors
  • Supraspinatus
  • Infraspinatus
  • Serratus lateralis
  • Deltoid
Trunk
Lumbar and Cervical Erectors
Quadratus Lumborum
Thoracic Erectors
Rectus Abdominis
Pelvis – Thigh
  • Hamstrings
  • Iliopsoas
  • Rectus Femoris
  • Thigh Adductors
  • Piriformis
  • Tensor Fasciae Latae
  • Vastus Lateralis
  • Vastus Medialis
  • Gluteal Muscles
Lower Leg - Foot
Gastrocnemius
Soleus
Anterior Tibialis
Peroneals
Extensors of the toes

When capsule and ligament structures become overloaded and damaged, the resulting tonic muscle facilitation commonly leads to characteristic holding patterns and faulty movement sequences. A classic example of this is seen in a postural holding pattern demonstrated by an elevated, forward-rounded shoulder with increased tone in the biceps, or increased postural elbow flexion. When someone has this holding pattern and they perform movements such as lat pull downs, chin ups, rows and shoulder abductions, the movement is usually initiated from the upper trapezius, evidenced by a shoulder-hiking action. During shoulder abduction, there is often increased effort from the upper trapezius at the beginning of the motion to carry the arm through mid and upper ranges of abduction; there may also be an associated pain with this movement.

How does this pertain to balance training? When practicing any balance exercise or drill, such compensatory recruitment patterns are commonly accompanied with posture that is not conducive to optimal skills development or maintenance of one’s center of gravity over their own base of support. For instance, many protective patterns resulting from joint instabilities in the body result in gradual pronation of one’s entire body. From a postural perspective, this constitutes forward head posture, increased pronation of the extremities and a reduced ability to support the body against gravity and kinetic loading.

Poor posture is detrimental to learning or maintaining a balance skill because any environment requiring maintenance of balance also requires three-dimentional freedom of motion in the spine in order to right oneself. Because extremity motions required to right oneself are generally acyclical, the ability to rotate the spine efficiently and effectively is essential to preventing unwanted falls. As you can see from Figure 2, anytime someone’s thoracic kyphosis is increased and/or they have forward migration of the head, rotational capacity and rotational efficiency will be reduced, thus reducing one’s ability to right themselves or balance!

Figure 2. Poor Posture = Poor Balance!

The problem of muscle imbalance and faulty joint motion is not just localized to a “dysfunctional joint complex.” Clinical experience demonstrates that such clients not only have an increased risk of injury while learning new and unfamiliar balance skills, but they may also complain of “abnormal nagging pains” of an unknown origin while learning or practicing such exercises. This is likely to result from faulty motor recruitment of muscles at distant locations.

In support of this contention, Dvorak and Dvorak have demonstrated something they refer to as a spondylogenic reflex syndrome. While under cervical traction, the researchers electrically stimulated mechanoreceptors at the C3-4 level and were able to record significant EMG (electrical activity) responses in muscles certain muscles including the sternocleidomastoid, trapezius, digastric, scalenes, triceps, rectus femoris and biceps femoris! These findings strongly suggest that the electrical messages sent to the brain may make it respond as if a corresponding preprogrammed pattern of motion were taking place. Dvorak and Dvorak identified this phenomenon as a distant recruitment pattern.

This relates to the fitness professional because any individual suffering from a muscle imbalance and an inability to maintain OIAR during a challenging balance skill may develop an idiopathic hamstring strain, groin strain, muscle tear or spasm in a seemingly unrelated region relative to the problematic joint. In other words, you could injure a client that has a muscle imbalance if you give them an ill-prescribed balance exercise!

Additionally, balance training drills in the presence of intrinsic imbalance are likely to predispose your client to injury outside the gym, secondary to facilitation of faulty motor sequencing.

GROSS STABILITY, MUSCLE CHAINS AND BALANCE

The body knows nothing of muscles, only of movement. During the continual changes that take place to preserve our equilibrium while moving, the body is constantly activating an array of muscles in patterns of coordination that causes muscles to lose their identity. When we train people using balance exercises, we are training hundreds of muscles at once.

Current research by Serge Gracovetsky and Andre Vleeming et.al. expands on previous knowledge of muscle chains presented by such anatomy experts as Raymond A. Dart. In Figures 3-6, specific chains of muscle are now referred to as outer unit muscle systems by these and other researchers. The outer unit muscle chains work synergistically with inner unit muscle systems to carry out motor commands from the CNS. (For more detailed information, please read my articles on The Inner Unit and The Outer Unit.) 

An understanding of outer unit systems and their working relationship with inner unit systems is necessary to understand how an individual or an athlete, such as a gymnast, can display impressive feats of balance (above) yet suffer from chronic musculoskeletal pain. In many cases they are predisposing themselves to injury by performing various balance acts while their body is out of balance at a segmental or gross level. Just because they can perform acrobatic feats of balance doesn’t mean they have inner structural balance, nor does it mean that repetitive exposure to further balance training is optimal for long term progress!

To appreciate how this works a little better, first consider that the small segmental stabilizer muscles have a profound influence on the recruitment of the larger outer unit muscles. For example, spindle cell counts of small muscles such as the suboccipital muscles in the anterior and posterior cervical region, and the intertransvarii and interspinales of the cervical and lumbar spine, have as many as 200-500 spindle cells per gram of muscle tissue! Using this information it becomes evident that one of their primary roles is to inform the CNS of joint position. As these position sensitive muscles discharge through the gamma nervous system they, along with local mechanoreceptors, have a profound influence on the alpha motor neurons of the larger muscles, which have the capacity to alleviate compression, torsion and sheer forces acting on any joint experiencing threshold limits of motion. 

Problems arise in these systems when athletes become more experienced at exerting themselves and therefore become progressively more able to ignore warning signals coming from within. Examples of this are Golgi inhibition override by experienced Power Lifters, and the fact that many gymnasts and martial artists are capable of performing amazing feats in the presence of intrinsic pain and dysfunction.

It must be remembered that pain is the most powerful and effective re-programming agent of the CNS and anytime you are learning a balance skill at the expense of segmental stability or in the presence of muscle imbalance syndromes, you are retarding the ability to effectively utilize the segmental and gross stabilizers of the body. More importantly, you are teaching the body to move in an environment in which pain avoidance is the primary goal, not optimal motor learning! 

As a clinician, I have had to treat scores of elite athletes in sports requiring exquisite balance skills, including motocross, skate boarding, ice skating, gymnastics, equestrian, hockey, skiing, surfing and martial arts. All of the athletes in these sports could perform amazing balance acts, yet they all came to me because they were in pain! To restore an athlete or individual’s ability to train for and participate in these sports, muscle balance and segmental stability training must precede balance skills development if long-term performance and injury prevention are the goals!

POSTURE AND BALANCE SKILLS DEVELOPMENT

The topic of posture is a complex one, but my goal here is to merely show you the intimate relationship between posture and balance training. To begin, I would like to point out that in nature, where animals function naturally, poor posture and poor balance are virtually unheard of (below).

Simply stated, posture is the sum total, or static and dynamic expression, of segmental and gross stability. At the segmental level, each joint complex maintains it’s own balance as expressed by the maintenance of an OIAR and must maintain a balanced working relationship with one another.

In an individual with poor posture (above, B), attempting to learn balance skills will only reinforce poor posture if they are unable to achieve optimal alignment and stability during the exercise! Ultimately, balance training in the absence of postural training and segmental stability perpetuates postural, joint and soft tissue dysfunction - the tonic muscles become progressively more facilitated while the phasic antagonists become progressively more inhibited, further degenerating length/force relationships. This is very important to remember because the body always moves toward its position of strength. Therefore, anytime you learn a new skill from a position of poor posture (balance skill or otherwise), you are merely reinforcing faulty biomechanical relationships and faulty motor skills development! In this case, the brain now seeks to generate an equilibrium reaction or to generate force from a position of poor posture (below).

Your client with poor static posture will demonstrate poor dynamic posture if therapeutic intervention and postural training are not implemented prior to structural adaptation taking place. For example, notice the kypholordotic posture presented by this roofer carrying a sheet of plywood across a rooftop, a situation that naturally requires axial extension or lengthening of the spine for optimal performance and injury prevention! It is important to have an appreciation for static vs. dynamic posture when attempting to improve balance in your client.

Part 2 of this article series takes a look at the basic reflexes of Righting and Equilibrium that we use during balance activities, and it will give us practical tools for building the right type of balance in our clients, from sedentary to elite level athletes.