Design of Study
An audit of the five providers (community health and fitness centres) in Melbourne, Victoria who had received accreditation to implement the Lift for Life program, and who had been an active provider for at least six months, was undertaken in February 2006. The audit encompassed the collation of data that had been collected for each participant in the respective facilities post-accreditation. This involved the photocopying of assessment forms for each participant who had received an initial assessment prior to commencing the program. During the audit process, it was identified that one provider had not complied with the intended assessment procedures and hence this provider was not included in the analysis. For the remaining four providers, the following information was collected for each participant: demographics (age, sex), waist circumference, upper body strength (arm curl test), agility (timed up-and-go) and lower body strength (chair sit-to-stand). For each participant the initial baseline assessment and the most recent assessment were obtained.
Accreditation
As a requirement of the accreditation process, all Lift for Life trainers attend a 2-day training workshop. Within this training, demonstrations of the testing protocols are reviewed along with the provision of written instructions. All trainers are required to provide a satisfactory level of competency with the testing protocols, as determined by a final written assessment.
Lift for Life resistance training intervention
Lift for Life is a progressive resistance training program structured over three phases of approximately eight weeks each (See Figure 1). In accordance with current resistance exercise guidelines for people with and without type 2 diabetes [12, 13] the program uses a similar resistance training protocol as the clinical trials [3, 11]. Lift for Life incorporates isotonic resistance training equipment (pin weighted machines and free weights) with an emphasis on continual progressive overload (increments of 2-10%). Participants attended exercise sessions in small groups of 8-12 people under the supervision of exercise trainers (Physiotherapists, Exercise Physiologists and experienced Certificate IV Personal Trainers) who have received specialized training, as part of the Lift for Life accredited process. Before commencement of the resistance training program, participants must obtain approval from a medical practitioner and undergo a baseline assessment conducted by the program provider. Participants are then prescribed a customised resistance training program and are gradually introduced to the program throughout the first 8-week phase. This phase requires participants to undertake two sessions per week, at which point the first phase finishes and another assessment is undertaken.
The participant's exercise prescription is then reviewed and a new customised program implemented before the participant commences the second 8-week phase; but with the goal of completing three sessions per week and ending with another assessment at week 16. The final phase is a replication of the previous phase, and if warranted, minor exercise prescription adjustments are made. Achievement of the entire program would result in a total of 24 weeks of resistance training and approximately 64 group sessions.
The cost of each session per participant varies among Lift for Life providers, and is approximately $10 - $15 AUD. Some private health insurers subsidise the cost of the program.
Subjects
A convenience sample was obtained from subjects who had participated in the program at their chosen local facility within the duration of 35 consecutive months, from February 2006 to December 2008.
Participants with severe orthopedic, cardiovascular or respiratory conditions that would preclude participation in an exercise program, or those with a medical condition listed in the American College of Sports Medicine (ACSM) absolute exercise contraindications [14] were not granted permission by their doctor to participate and thus were also excluded. The study was approved by the International Diabetes Institute Ethics Committee, and written informed consent was obtained from all participants. Overall, 86 participant were recruited for the study.
Testing Procedures
Anthropometry and Body Composition
Existing equipment located in the respective facility was used to ascertain anthropometric measures. Within the Lift for Life procedures, height (cm) was measured using a stadiometer and body weight (kg) was assessed using calibrated scales to the nearest 0.1 kg. Waist circumference was measured using a non-elastic measuring tape at the mid-point between the lower border of the ribcage and the iliac crest. All of the data were collected by the program providers.
Functional measures
A validated battery of three physical test items [15], developed specifically for older adults, was used to assess aspects of functional fitness. These tests included: chair sit-to-stand (number of complete movements undertaken in 30 seconds; lower body strength), arm curl (number of complete movements undertaken using a standard dumbbell weight in 30 seconds; upper body strength) and timed up-and-go (agility course over 8 feet - time taken to complete).
Statistical Analysis
Statistical analysis was conducted using Stata version 10.0 (STATA, College Station, TX, USA). The net differences were calculated by subtracting the changes from baseline for each time point (week 8, week 16, and week 24 assessments). Descriptive data at baseline was analyzed using paired t-tests. The time effects for anthropometric and functional variables were examined using pooled time series regression analysis for longitudinal data with random effects models. Missing baseline data were replaced with the mean measurement for the respective variable for the total group: waist circumference (1 imputation), chair sit-to-stand (1 imputation), arm curl test (2 imputations) and agility - up-and-go test (3 imputations).