Effect of six weeks of resistance training on bone preservation in older adults: a randomized control trial.

BACKGROUND: It has been established that chronic resistance exercise contributes to positive changes to bone in older adults. AIMS: This study evaluated the effect of 6 weeks of resistance exercise with either elastic bands or dumbbells vs. a control period on bone morphology of older adults. METHODS: Fifty-seven adults (mean ± SD; age = 66.5 ± 7.09 yrs; height = 165.2 ± 10.6 cm; body mass = 74.5 ± 14.6 kg) were randomized into three groups (dumbbell, elastic, or control). Participants underwent a total body dual-energy X-ray absorptiometry (DXA) scan for total body and segmental bone mineral content (BMC) and bone mineral density (BMD) before and following 6-week intervention. Age-matched Z-scores for BMD and BMC were recorded. Data were analyzed using two-way repeated measures ANOVAs and 0.05 significance level. RESULTS: BMCarm improved for the dumbbell group (p = 0.016) after the training, with no change in BMD for any group (p > 0.05). Additionally, significant (time x treatment group) interaction (p = 0.024) of age-matched Z-scores indicated an improvement in only the dumbbell group after 6 weeks (p = 0.015), with no change in the elastic group despite them having greater Z-scores than the control group. DISCUSSION: This study is the first to demonstrate acute normative adaptations as dumbbell-based programs may promote positive maintenance of bone metrics over 6 weeks, despite the lack of significant change in absolute BMC or BMD. CONCLUSION: Adults did not lose relative bone mass with acute exercise using dumbbells as the external load applied and this may lead to positive changes following chronic training. There was no bone-related impact from elastic bands, suggesting a weighted load or force produced relative to gravity is beneficial.

Skeletal muscle analysis of panoramic ultrasound is reliable across multiple raters.

Ultrasound devices are common in muscle physiology laboratories due to their ease of use and validity to assess skeletal muscle characteristics. The current study assessed the reliability of ultrasound skeletal muscle image analysis across multiple raters with limited experience. Vastus lateralis (VL), rectus femoris (RF), and first dorsal interosseus (FDI) images were separately analyzed by three novice raters to determine muscle thickness (MT), cross-sectional area (CSA), and echo-intensity (EI). Separate analyses of variance (ANOVA) assessed statistical differences between and within raters. Intra-class correlation coefficients (ICC) between (inter-rater) and within (intra-rater) raters, the standard error of the measurement (SEM) and minimal difference needed to be considered real were calculated. Inter-rater reliability was high for the VL and RF (ICC: 0.984-0.999), while the FDI was lower (0.614-0.962). Further, intra-rater reliability was greater than 0.961 for each rater. SEM values calculated for inter-rater reliability expressed as a percentage of the mean ranged from 0.4-5.8% across variables. Similarly, SEM values for intra-rater reliability were between 0.8-5.8%, 0.6-3.6%, and 0.4-3.2% for Raters 1, 2 and 3, respectively. Despite this, significant differences (p<0.05) between raters were observed for RF MT and EI, VL CSA and EI, and FDI MT, suggesting that potentially more measurement trials or greater practice time may be necessary to reduce systematic error among multiple raters. Post-image acquisition processing is reliable among and within raters as determined through ICCs and SEMs. This study provided consistent results among three separate novice raters given the same training, a unique yet realistic setting in muscle physiology laboratories.

Short-term resistance training in older adults improves muscle quality: A randomized control trial.

The purpose of this study was to evaluate whether dumbbell resistance training (DBRT) and elastic band resistance training (EBRT) are equally beneficial in the older adult. Sixty-five healthy participants (mean±SD; age=66.5±7.09 years; height=165.2±10.6 cm; body mass=74.5±14.6 kg) volunteered for this study. Participants underwent a total body dual-energy x-ray absorptiometry (DXA) scan for segmental and total body muscle and fat estimation. Functional tests included the short physical performance battery, timed up-and-go, and heel-to-toe walk. Strength was measured on dominant handgrip strength, maximal bench press, and leg press. Participants were block randomized into one of three groups: elastic band resistance training (EBRT), dumbbell resistance training (DBRT), or control (CON). EBRT and DBRT were asked to visit the laboratory twice weekly over 6-weeks while CON maintained their daily routine. Data were analyzed using a two-way repeated measures ANOVA and an alpha set at 0.05. Results indicated there was a two-way interaction for bench press, leg press, upper- and lower-body muscle quality and total arm lean mass (p<0.05). Specifically, the EBRT and DBRT improved from pre to post for total arm lean mass (p<0.021, p<0.004, respectively). Additionally, for bench press and leg press, all groups improved pre to post training (p<0.05) with DBRT superior to CON. These data suggest that EBRT provides an effective, portable, and cost-effective means to enhance lower-body function and muscle quality in an aging population, yet DBRT may be more impactful for total-body improvements.