RESEARCH
CAN LOW LOADS STRENGTHEN
OLDER CLIENTS’ BONES?
Higher-load resistance training has been shown to help maintain and improve
bone mineral density, but can low-load training have the same effect?
Research paper: Low-load very highrepetition resistance training maintains lumbar
spine bone mineral density in active postmenopausal women
Research team: Vaughan P Nicholson, Mark R
McKean, Gary J Slater, Ava Kerr, Brendan J
Burkett
Published: Calcified Tissue International
Read more: DOI 10.1007/s00223-015-9976-6
Introduction: Age-related reductions in
bone mineral density (BMD) occur at most
skeletal sites after the third or fourth decade
in men and women and such reductions
are typically accelerated in women after
menopause. Fortunately, it is now well
established that resistance training can help
maintain and improve bone mineral density
in post-menopausal women. Typically, highintensity (or high-load) training interventions
using training loads over 75-80 per cent of
one-repetition-maximum (1RM) have been
more successful at improving BMD when
compared to low-load training (<50 per
cent 1RM) interventions, although the lowload interventions assessed have also used
relatively low repetition ranges. Interestingly ,
when training volumes are equivalent both
low- and high-load training may be similarly
effective at improving BMD.
Low-load very high-repetition resistance
programs such as BODYPUMPTM are
available in over 14,000 fitness facilities
64 | NETWORK WINTER 2015
globally. This pre-choreographed group
class uses light weights and very high (80100) repetitions for each exercise, so it
provides a platform to assess the effect of
low-load very high-repetition resistance
training and as recent trends indicate that a
growing number of over 55s are undertaking
fitness facility-based activities, the apparent
effectiveness of such activities warrants
examination. Furthermore, social factors
are a key motivator for exercise participation
in middle-aged and older adults so
participation in a group class may promote
greater compliance among participants and
provide prolonged benefits.
Methods: Apparently healthy women
aged between 58 and 75 years were invited
to take part in the study. All participants were
recruited through local advertising and an
adult education facility. All participants were
physically active non-fallers who had not
undertaken formal resistance training in the
previous year. All women were at least five
years post-menopausal and provided details
of medical history and current medication
use. Exclusion criteria included: acute or
terminal illness, myocardial infarction in the
past six months, recent low impact fracture,
osteoporosis, use of hormone replacement
therapy (HRT) and other medications known
to affect bone metabolism in the previous
two years, or any condition that would
interfere with moderate intensity exercise
participation. A total of 50 women took
part in the intervention and were allocated
to either the intervention group (PUMP) or
control group (CON). PUMP participants
were instructed to attend two BODYPUMPTM
classes per week for six months.
Participants were tested on two
occasions: the first assessment was
conducted prior to the beginning of training
and the second assessment was conducted
immediately after the six-month intervention.
Body composition assessments were
performed using dual energy x-ray
absorptiometry (DXA – see feature on DXA
in Network Autumn 2015). Participants were
overnight-fasted and had not undertaken
any exercise on the morning before
measurements. Bone mineral density of the
lumbar spine (antero-posterior L2-4) and
hip (femoral neck, total hip and trochanter)
were assessed. Assessment of 1RM was
conducted for the incline leg-press (Calgym,
Australia) and Smith machine bench press
(Elite, Australia).
Dietary intake was assessed from selfreported three-day food records completed
at baseline and follow-up. Participants were
instructed to record the type and amount of
all food, drink and supplements consumed
over three consecutive days. All records were
entered into FoodWorks 7 (Xyris Software,
Australia) and daily consumption of total
energy (kJ), protein (g/kg body weight)
and calcium (mg) were analysed. Energy
expenditure derived from exercise and
physical activity was estimated by a sevenday activity diary. A metabolic equivalent
value was assigned to each activity and was
used to determine the average amount of