The Medical Science behind Nymbl’s approach to Balance Improvement

THE MEDICAL SCIENCE BEHIND THE NYMBL DUAL TASKING APPROACH TO BALANCE IMPROVEMENT

 

Research on the Dual Tasking approach to balance improvement, and Nymbl’s Unique method of implementing this for users

This page outlines the available research on dual tasking interventions and balance improvement, and how this research is implemented in the Nymbl System.  We have also conducted studies of the Nymbl Balance improvement, which are summarized on our Validation of the Nymbl Balance Platform article.

Research Confirming that Dual Tasking significantly improves balance

The following primary research demonstrates that dual tasking has positive and lasting effects on balance.

Journal of Neurologic Physical Therapy
“Results show that Dual Task Training improves single-task gait velocity and stride length in Parkinson’s Disease (PD) and Alzheimer’s Disease (AD), dual-task gait velocity and stride length in PD, AD and brain injury, and may improve balance and cognition in PD and AD.”

 

This meta review of many primary research studies on Dual Task Training summarizes that in virtually every study, Dual Task Training showed a measurable and significant improvement when compared to single task control groups, as shown in this table
summary of dual task studies and balance
The forest plots above show the compelling evidence from multiple studies that Dual Task Training provides superior results in Balance and Gait Training
Training of Balance Under Single- and Dual-Task Conditions in Older Adults With Balance Impairment
Patima Silsupadol, Ka-Chun Siu, Anne Shumway-Cook, Marjorie H Woollacott
Physical Therapy, Volume 86, Issue 2, 1 February 2006
“The patients who received balance training under dual-task conditions showed dual-task training benefits; these training benefits were maintained for 3 months.”

 

Working Memory and Postural Control: Adult Age Differences in Potential for Improvement, Task Priority, and Dual Tasking
Michail Doumas Michael A. Rapp Ralf Th. Krampe
The Journals of Gerontology: Series B, Volume 64B, Issue 2, 1 March 2009
“These findings demonstrate the adaptive flexibility in older adults’ resource allocation and a persistent potential to bring this flexibility to bear in challenging situations despite age-related constraints in resource availability. “

Dual tasking approach in the Nymbl System

Nymbl combines simultaneous isometric exercise with cognitive training to improve balance by:
– strengthening core muscle groups required to stand erect and maintain a good walking posture
– improving flexion of muscles needed for correct spine alignment
– stimulating the cerebrum & cerebellum through the double attention required to:

1. hold the body in certain positions and

2. solve cognitive puzzles

Isometric Exercise and Core Muscle Strength

What does isometric mean? In simple terms, muscle can only contract in a few ways: (1)
– eccentric and concentric contraction where the muscle tenses by lengthening and shortening -e.g. moving limbs up and down,
– isometric contraction, where the muscle tenses while not changing length, e.g. pushing against an immoveable object such doing a wall sit, or a static lunge.

While it may seem that because no movement is involved, isometric exercise cannot be doing any good, in fact the benefits of isometric training are well researched and documented and have the added advantage of needing no specialist equipment.

The Journal of Applied Research shows that isometric exercise improves muscle strength faster than dynamic exercise.(2) Energy is only spent on increasing tension in the muscles without it being wasting on motion causing fatigue, therefore, making it possible to reach maximum levels of strength in minimum time. Isometrics increase flexibility and decrease injuries. They require body and brain to fire up all muscle fibres in a maximal voluntary contraction to succeed.(3) Furthermore, between lunges, wall sits and unipedal stands a high number of key muscle groups are engaged (see Nymbl Exercises and Muscle Groups information sheet)

Posture & Spine Alignment

Correct posture and spine alignment can be seen in figure 1. If the head’s centre of mass is not maintained on the body’s line of gravity then posture becomes as in figure 2. As Dr Farcy explains “The body’s balance for a major part is maintained by the cervical action of all neck muscles, insuring the inner ear’s vestibular stability when acceleration is transmitted to the head by body motion. Head control does not only guarantee good function of the oculo-vestibular reflex, it ensures enlarged perception of the environment, and by extension of its specific input at each given moment.” (4)

Fig. 1

Fig. 2

Fig. 3

Nymbl exercises keep the head up and the gaze horizontal through the action of holding arms stretched out and focusing on a screen at eye-level (fig. 4.)

Fig. 4

Fig. 5

 

Figure 3 shows the head up but a flat back – the curve of the lumbar spine is no longer maintained and the centre of gravity has shifted. A person will stay upright like this – they are still within the cone of balance (fig. 5) but the further they are towards the outer extremities the more vulnerable they are to falling.

Returning a moment to figure 1 you see the lower red arrow indicating the relationship between the reverse stretch of the hip flexor and the correct lordosis (also known as “sway”) or curve of the lumbar spine. Figure 3 illustrates what happens when that extra flexion in the hip (known as the reserve extension) is no longer there. Nymbl lunges with hip flexors stretched back, torso upright, neck muscles keeping the head over the centre of gravity, help correct this. (5) (6)

Isometric Exercise and proprioception

Proprioception is our sense of the relative position of one’s own parts of the body and strength of effort being employed in movement. The proprioceptors are sensors that give the brain information about the position of the limb in space at any given time. “Many neural pathways synapse at various levels of the central nervous system, integrating all this information to provide us with both a conscious and non-conscious sense of where we are and how we are moving.” (7)

Clearly this aptitude is vital for good balance. These two aspects of proprioception – conscious and unconscious – are both vital for safe activity but they become impaired as we age. Falls frequently result when the brain of a senior is ‘overloaded’; for example, they are in the middle of walking and something unexpected happens. Isometric exercise requires conscious effort and concentration to hold positions without flagging or falling and this stimulates the cerebrum – the part of our brain that controls all voluntary actions in the body – then the Nymbl system adds in removal of visual context (asking you to close your eyes) or an additional cognitive load, such as asking you to answer quiz questions. This deliberate ‘overload’ forces the brain to move the conscious concentration on the holding the exercise pose into unconscious activity whilst it consciously focuses on solving puzzles. This stimulates the cerebellum which is responsible for coordinating the unconscious aspects of proprioception, ergo, often attributed as responsible for balance.

The effects of proprioceptive training on improving motor function are widely researched. (8)

Brain Plasticity, Isometric training & cognitive exercise

“The non-conscious sense of embodiment is essential for timely, appropriate neuromuscular coordination” (9) and whilst it was second nature when we were young, in age it declines, impairing our balance and making us vulnerable to falls. At the heart of this decline is the closing down of synapses in our brain, or in other words, reduced brain plasticity.

Isometric exercise already requires the integration of a huge amount of information from our muscles, vision, perception, vestibular system, in milliseconds by the brain. Adding an extra cognitive load in the form of puzzles, quizzes, and games enhances the stimulation of the synapses which improve brain plasticity.

 

Notes
(1) Human Physiology: From Cells to Systems, Lauralee Sherwood
(2) Journal of Applied Research 2006 “In fact, using isometric exercise for 6 minutes would be the equivalent muscle work of 30 to 35 minutes of gym work on commercial weight lifting equipment.” https://bdxbiomechanics.com/isometric-research-studies/
(3) See Thépaut-Mathieu C(1), Van Hoecke J, Maton B for studies on increased strength, power and muscle mass through isometric training
(4) (a) text book name “The wide sweep of a gaze of the eye with the multiple degrees of freedom of movement of the head, is one of the best guarantees of a continuous enrichment of cognition”
(5) The hip extension criteria are well documented by Istvan Hovorka’s research text book name ( chapter 7 )
(6)  Stretching your hip flexor is a good start towards pelvic alignment. https://healdove.com/disease-illness/The-Importance-of-Reversal-of-Cervical-Lordosis
(7) International Association for Dance Medicine & Science
(8) The effectiveness of proprioceptive training for improving motor function: a systematic review – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4309156/
(9) International Association for Dance Medicine & Science