and a single-leg Romanian deadlift in the many programs I had to
write for him. His argument was simple: if you can bench press 100kg
with two hands, you cannot dumbbell press close to half of that
without flipping off the bench, so the exercise has ‘limited value 14 ’ for
strength development.
Poliquin highlights the majority view of that time – in many
instances of unstable training, the load able to be lifted is dramatically
reduced such that the prime movers are not sufficiently overloaded.
This has obvious implications if one has the training goal of strength,
power and hypertrophy – as muscle motor unit (MU) recruitment is
paramount for a training effect.
Numerous studies published over the years have supported this
general claim. Research has shown that although neuromuscular
activity remains similar between stable and unstable training, the
MU recruitment of the prime movers is reduced and shifted towards
the core and peripheral muscles (normally those muscle groups in
contact with the stable surface, such as the floor).
Indeed, an early study by Professor Stuart McGill and colleagues
showed that a standing single-arm cable chest press produced
65% less force production than a lying bench press 15 . Standing
pressing exercises have been shown to be limited to 40% of the
individual’s bodyweight, and that is why strength coaches of elite
shot putters, for example, use bench pressing exercises to develop
upper body pushing strength, often in excess of 240kg. Furthermore,
the study found that the bench press highly recruited the pectoral
and deltoid muscles – much more so than the core. The standing
single-arm press had internal oblique and latissimus dorsi activity
levels similar to the pectorals and deltoids in the bench press. The
researchers found that the limiting factor for the unstable exercise
was maintaining whole-body stability together with joint stability. If
the goal was upper body strength or muscle mass development of
the chest and deltoids, clearly, the bench press derivatives would
be the primary choice. If joint and muscle group stability or wholebody
equilibrium was the goal, the destabilising traditional exercises
would provide the advantage.
No advantage for strength or power
David Behm and colleagues recently conducted a meta-analysis on
unstable training and reported that there was no advantage of unstable
training for the development of maximal strength or power 16 . Behm
concludes that ’the application of unstable training compared with
traditional strength training has limited additional effects on measures
of muscle strength, power and balance in healthy adolescents and
young adults. Therefore, the use of unstable as compared with
At its core, functional
training proposes that the
body knows movement
and not muscles
stable surfaces during strength training is
only partially recommended’. This word
‘partial’, as a coach, is important. In certain
instances, where you desire lower joint
forces (rehabilitation) or higher stability or
core activation (correcting imbalances or the
GPP), then unstable exercise choices would
be advisable.
This has a message to both sides in
the strength industry. To those who feel
that traditional strength exercises such as
squats, deadlifts, presses and pulls are all
that is needed to challenge all motor abilities,
including core muscles and joint and muscle
stabilizers, the data strongly argues against
this viewpoint.
For those who feel that strength program
design should be only functional, with all
machines replaced by unstable, unilateral
and functional derivatives, then the literature
suggests that maximal strength, power and
muscle hypertrophy will be compromised in
favour of stabilising muscle groups.
Lessons for exercise selection
What conclusions can we draw on exercise
selection from studies investigating muscle
recruitment levels across various stable
and unstable tasks? Here are my practical
take-home messages for the strength
coach and trainer:
NETWORK WINTER 2020 | 21