PRIME: A Novel Low-Mass, High-Repetition Approach to Improve Function in Older Adults

Abstract

Introduction: The ability to maintain functional independence in a rapidly aging population results in an increased life expectancy without corresponding increases in health care costs. The accelerated decline in V˙O2peak after the age of 65 yr is primarily due to peripheral tissue changes rather than centrally mediated factors. The purpose of this study was to determine whether the Peripheral Remodeling through Intermittent Muscular Exercise (PRIME) approach, consisting of a low-mass, high-repetition/duration skeletal muscle focused training regimen would provide superior functional benefits in participants older than 70 yr old and at risk for losing functional independence.

Methods: In this clinical trial, 107 participants were randomized to 4 wk of either standard aerobic training (AT) or PRIME (phase 1). This was followed by 8 wk of a progressive whole-body aerobic and resistance training (AT + RT) for all participants (phase 2). The major outcome measures were cardiorespiratory fitness (peak oxygen consumption [V˙O2peak]), muscular fitness (1 repetition maximal strength [1RM]), and physical function (Senior Fitness Test [SFT] scores). Results were analyzed under a per-protocol criterion.

Results: Thirty-eight PRIME and 38 AT participants completed the 3-month protocols. V˙O2peak, 1RM, and SFT scores all increased significantly after 12 wk for both treatment groups (P < 0.05). However, relative to AT, participants randomized to PRIME demonstrated a greater increase in V˙O2peak (2.37 + 1.83 vs 1.50 + 1.82 mL·kg·min, P < 0.05), 1RM (48.52 + 27.03 vs 28.01 + 26.15 kg, P < 0.01) and SFT (22.50 + 9.98 vs 18.66 + 9.60 percentile, P < 0.05).

Conclusions: Participants experienced greater increases in cardiorespiratory and muscular fitness and physical function when PRIME training was initiated before a combined AT + RT program. This novel exercise approach may be advantageous to individuals with other chronic disease conditions characterized by low functional capacity.

Conflict of interest statement

CONFLICT OF INTEREST

All authors have no conflicts of interest to disclose

The results of the present study do not constitute endorsement by ACSM

T the results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation.

Figures

Figure 1

CONSORT schematic of the PRIME Study. Thirty-eight subjects in each treatment arm had complete datasets and were included in the final analysis. *Spousal randomizations were when couples wished to be enrolled in the study together and desired to be guaranteed in the same intervention group. In these cases, in order to adhere to the randomization schedule, we only included the data from the primary subject, who was determined at random. This “allocation” was unknown to the study staff and the participants.

Figure 2

The average time spent in the target heart rate range during each exercise session for (a) Phase 1 and (b) Phase 2 of the intervention protocol. Data are presented mean ± SD and statistical significance is denoted as (**, p

Figure 3

Group mean data adjusted for baseline values at the initial testing visit prior to randomization (left column) and waterfall graphs of individual training response to PRIME and AT treatment (right column). Top panels (A & B) represents peak cardiorespiratory capacity (VO2 ml·kg−1·min−1); Middle panel (C & D) represents the combined maximal voluntary contraction of respective strength assessments (kg); and the bottom panel (E & F) represents the percentile ranking for the Senior Fitness Assessment (%). Data are presented mean ± 95%CI and statistical significance is denoted as (*, p<0.05, ** p<0.01) for PRIME vs. AT from group mean increase at 12 weeks in comparison to Baseline.