training is always context-dependent and merely deciding that an
exercise is functional if you carry your centre of mass over your base
of support, or you destabilise the movement, is an extraordinarily
unhelpful and simplistic way of looking at exercise selections.
Practice the actual activity
Siff was one of the first to note that there is no such entity as a truly
functional exercise, except for the actual sporting or daily movement
that we are trying to enhance by training. Siff also argued that many
of the tools (exercises, equipment and accessories) used in current
functional training have long been employed in rehabilitation and
conditioning programs and that, therefore, little is actually new.
Other experts, since Siff, have stated that the optimal method to
promote increases in balance, proprioception and spinal stability
for any given sport is to practice the skill itself on the same surface
on which the skill is performed in competition. In his classic paper
on power, Professor Schmidtbleicher stated that intermuscular
coordination can only be developed by practising the movement for
which coordination is sought 5 .
Function in action and in muscle
In line with the principle of training specificity, functional training or
SPP exercises should reflect movement velocity, contraction types
(i.e. concentric, eccentric, or isometric), and intensities (strength vs.
endurance needs), joint angles, balance challenges, range of motion,
and other applicable capacities. Any exercise can be categorised as
functional if it develops strength, power, balance, motor coordination,
endurance, or improves the ability of individuals to execute activities
of daily living (ADLs), whether they be simpler tasks or more complex
athletic manoeuvres.
Another way I have looked at the classification of functional is that
any exercise can be deemed functional if it improves the function
of muscle or the capacity of the system it targets. In support of
this viewpoint are the majority of the early studies examining the
effects of traditional strength training on activities of daily living in
the elderly population. These studies have convincingly showed that
machine-based resistance training dramatically improved strength,
power, balance and muscle mass which transferred to the ability to
carry bags, prevent falls, safely climb stairs and rise from a seated
position. In other words, machine resistance training, which is by
any definition non-functional, improved functional capacity in this
population.
Destabilising – and decreasing
With respect to destabilising strength exercises, unstable exercisebased
programs have been shown to decrease force and power
output by around 30% compared with comparable traditional
strength training 6 . This negative aspect makes unstable training
more suitable for rehabilitation, as the instability-induced decrease in
strength and power output provides a healthy stress on a recovering
joint or muscle. For example, Cholewicki and McGill showed that
the multifidus strength can be improved with training loads as low
as 30 to 40% of maximal voluntary contraction 7 . These lower force
outputs are suitable for back rehabilitation, while the increased trunk
and limb muscle activation provide greater stabilisation. Behm and
Colado reported a 47% increase in trunk stabiliser muscle activation
with unstable resistance training 8 .
Behm has also conducted several studies on beginners to
resistance training and showed similar gains in strength and muscle
mass between stable and unstable exercises. These findings, similar
to exercises used in rehabilitation, support the idea that beginners
can develop appreciable muscle and strength at much lower levels
of muscle activation than well-trained individuals 9 . It appears that
this is only effective during the early stages of training 10 , as losses in
strength and power have been repeatedly reported when experienced
lifters use unstable exercises, as there is a shift from prime mover
activation to favour core and stabiliser muscle recruitment 11 .
Professor Behm has also shown that programs comparing
unstable training with traditional stable strength training did
not provide balance advantages, irrespective of the age group
considered. This is most likely due to the fact that traditional
strength training provides moderate levels of instability, owing to the
placement and movement of bars or dumbbells on the shoulders,
overhead or in front of the body. Free weights place a disruptive force
outside the centre of mass, challenging the neuromuscular system to
maintain balance and equilibrium. Although the challenges to postural
stability are normally much greater during unstable exercises,
Behm demonstrated that this greater degree of balance challenge
does not lead to greater systematic balance improvements 12 . Other
studies 13 that have directly compared stable with unstable training on
measures of strength and muscle activation generally conclude that
there is ‘little support for training with a lighter load using unstable
loads or unstable surfaces.’
Metabolic impact
Similar findings have been replicated with respect to metabolic
health. The ability to control glucose levels in the blood, lower blood
pressure or improve other cardiovascular parameters is independent
of the type of resistance training performed. Put another way, our
blood glucose does not know if the muscle contraction came from leg
presses (machine), squats (free weights) or squatting on an unstable
surface (functional training). To metabolism, muscle contraction is
muscle contraction.
An unstable argument for strength development
In the mid 1990’s I had been heavily influenced by Paul Chek and his
reasonings for adopting a functional approach to exercise selection. I
had used many of these unstable exercises with clients, with varying
degrees of success. My viewpoints began to change when my
continuing education took me to Arizona at the beginning of the new
millennium to study under the late renowned strength coach Charles
Poliquin. He challenged the inclusion of a single-arm dumbbell press
20 | NETWORK WINTER 2020