It may be advisable to avoid pronation of the hand during the dumbbell biceps curl
Form following function when
it may not have to
2
The concept may become clearer if we look
at an exercise in which form follows function,
but for the purposes of weight training
doesn’t actually have to. A good example
is when the hand is pronated during the
concentric phase of a dumbbell biceps curl.
It’s not uncommon for trainers to advise that,
since the biceps pronates the hand as well
as flexes the elbow, a dumbbell biceps curl
should also pronate as it progresses. It’s
certainly true that a function of the biceps is
to pronate the hand, so if form had to follow
function strictly, a pronation should occur
during the curl. However, there are some
good reasons why it may not be advisable
to pronate a dumbbell biceps curl if you are
seeking basic biceps development.
Firstly, if you pronate on the way up, your
hand has to be at least partially supinated
at the start. You’d probably be starting the
curl with your palms facing your body. That
means that the first part of the curl would
be more like a hammer curl than a dumbbell
biceps curl and a hammer curl tends to use
forearm muscles more than biceps muscles.
Only when your hand supinates (turns) will
the biceps be flexing the elbow and working
as hard as it can be – but by then half of the
exercise is over, and your biceps will only
have been under load for around half the
distance of the curl.
Secondly, if you supinate the hand as you perform a biceps curl,
the supination becomes a counterweighted exercise. That is, while
your supinating muscles may be working a little harder to raise the
bottom end of the dumbbell (near your pinkie) as your wrist turns, the
top end (near your thumb) is actually travelling downwards, countering
the bottom weight and making the supination much easier. Finally,
the part of the biceps that pronates the hand is relatively small.
Supination is not a gross movement using a large amount of muscle,
so if you want well-developed biceps it may not be worth adding
the supination. In other words, if form completely follows function in
this exercise, you are unlikely to develop the strength and size you’re
after in the main part of the muscles you’re targeting.
The solution here is to supinate your hand from the beginning of
the exercise. With a supinated hand and a fully extended elbow, your
biceps will be working much harder through a much longer range
of motion as you perform the curl. Form will still follow function to a
very large extent – you’re doing a barbell curl after all – but for the
sake of the ultimate outcome, you shouldn’t pronate your hand just
because pronation is a function of the biceps. If you must work your
supinating muscles, do so separately with a one-ended dumbbell or
a cable, so that the exercise isn’t fully counterweighted (unless there
are rehab or sports-specific reasons that a pronating dumbbell curl
is programmed.)
If form completely follows function in this exercise, you
are unlikely to develop the strength and size you’re after
in the main part of the muscles you’re targeting
NETWORK SPRING 2018 | 13