It is well established that aging induces a loss of skeletal muscle across a lifespan. The
two primary considerations in attenuating this loss of skeletal muscle are nutritional
intake, specifically protein consumption, and physical activity levels, specifically
resistance training. Both of these factors have been shown to improve skeletal muscle
adaptation outcomes in older adults. One primary consideration in the skeletal muscle loss in
older adults is the concept of anabolic resistance, suggesting that older adults require a
greater amount of protein consumption to elicit similar rates of muscle protein synthesis as
compared to their younger counterparts. From this study, the investigators hope to reveal the
effect between protein intake graded to resistance training vs constant protein intake at the
recommended daily allowance in conjunction with the same resistance training protocol on body
composition. The purpose of this study is to examine the skeletal muscle adaptations that
occur in older adults consuming protein graded to resistance training volume as compared to
older adults who consume protein at a constant level while resistance training (RT). Our
hypotheses are:
Protein intake graded to RT volume will enhance skeletal muscle adaptation in older
adults to a greater degree than those consuming protein at a constant rate, as measured
via lean soft tissue mass assessed by dual energy x-ray absorptiometry (DXA)
Older adults consuming protein graded to RT volume will enhance strength to a greater
degree than those consuming protein at a constant rate, as measured via isokinetic
dynamometry and 3 repetition maximums of select exercises.
Older adults consuming protein graded to RT volume will see a greater change in muscle
tissue thickness compared to those consuming protein at a constant rate, as measured via
muscular ultrasound.
Community dwelling older adults (>55 years; men and women) who have not adhered to a
progressive RT program in the last 3 months will be recruited for participation in this pilot
study (n=20). All women recruited will be post-menopausal. In an initial telephone screening,
participants will be assessed for eligibility criteria, and it will also be determined
whether they are willing to be randomized into either of the two groups. The requirements of
each intervention group will be explained in detail. Participants will be assessed for
willingness to make necessary alterations to their diet, willingness to adhere to RT
protocol, and willingness to consume the necessary amount of protein supplement. Once
participants are recruited, they will be subsequently randomized using a web based program
(https://www.randomlists.com/team-generator) wherein group assignments will be placed in
numbered envelopes and opened by an independent researcher. This will be used to randomize
participants to one of the two experimental groups. This randomization and assignment will be
completely random, and not stratified to any subset of variables. All groups will complete
the same resistance training protocol. Overall study design, resistance training protocol,
detailed nutritional protocols are outlined in the tables submitted in supporting documents.
Briefly, all participants will be assigned a 10-week RT protocol, adhering to the 2009
Position Stand from the American College of Sports Medicine, based on their baseline tested 3
repetition maximums. Participants in the graded protein intake group will be provided a
certain amount of Whey Protein (WP) supplement to consume post-training session on training
days, and between meals on non-training days. The control group will not receive WP
supplement, whereas the intervention group will receive 25 g of WP supplement per day
beginning at week 1 and will progress to 75g of WP supplement/day by week 10 of the
intervention. This supplementation will assist overall protein intake, as the control group
will consume a constant 0.8g/kg/day throughout the course of the study and the intervention
group will consume 0.8 g/kg/day at week 1 and progress to 2.2 g/kg/day at week 10. For
example, an 80 kg individual will consume a total of 176 g of protein/day at week 10, with 75
g of this protein coming from supplementation, and the additional 76g coming from dietary
intake throughout the day. Should prescribed supplementation exceed the 2.2 g/kg/day
threshold, adjustments will be made in protocol to accommodate proper protein intake. The
investigators expect no adverse effects on renal and liver function as a result of increased
protein intake based on the findings of a recent meta analysis by Devries et al. (2018).
Additionally, participants will consume a ~500 kcal surplus per day to ensure adequate energy
for protein accretion and recovery.
Covid-19 Protocol:
Investigators, study staff, and participants alike share responsibility for the health and
safety of each other in an exercise/testing space. Maintaining a consistent six feet of
distance; wearing face coverings that cover our mouths and noses; limiting our gathering
sizes; and isolating or quarantining when ill or exposed to someone with the virus are Wake
Forest University directives and policies investigators, study staff, and participants all
must follow. Participants are encouraged to visit Our Way Forward to stay informed about the
latest guidance and stay up to date regarding public health policy. The study team will
follow guidelines set forth by public health officials.
Specifically, in this study, investigators, staff, and participants will mitigate the risks
of virus transfer and take care of our community by abiding by the following safety
directives:
maintain six feet of distance at all times when feasible.
wear a face covering for the entirety of time indoors and out. This face covering should
cover your mouth and your nose, and adhere to our University face covering policy (no
face shields without masks; no neck gaiters; no bandanas; and no masks, including N95,
with a one-way valve).
stay out of sessions when sick or after being exposed to someone who is sick.
In this study, any participant who does not follow these requirements will be asked to follow
the safety directives.
Participants will be offered a mask should they not have one.
If participants do not comply, they will be asked to leave the study space out of an
abundance of caution in regard to other participants and study staff.