Effect of Functional Impact Training on Body Composition, Bone Mineral Density, and Strength in Breast Cancer Survivors

Ashley L. Artese; Rachael L. Hunt; Michael J. Ormsbee; Jeong-Su Kim; Bahram H. Arjmandi; Lynn B. Panton

Disclosures

Med Sci Sports Exerc. 2021;53(1):90-101. 

In This Article

Abstract and Introduction

Abstract

Purpose: The purpose of this study was to examine the effects of 24 wk of functional impact training (FIT) that consisted of resistance and high-impact exercises in comparison with yin yoga on body composition, bone mineral density (BMD), blood biomarkers for bone metabolism, and strength in breast cancer survivors (BCS).

Methods: Forty-four BCS (60.3 ± 8.3 yr) were randomly assigned to the FIT or yin yoga group. Body composition and BMD were measured via dual energy x-ray absorptiometry. Blood biomarkers for bone metabolism were analyzed via enzyme-linked immunosorbent assays. Upper and lower body strength was assessed using a one-repetition maximum chest press and isokinetic knee extension/flexion using the Biodex System 3, respectively. Participants completed 45-min FIT or yin yoga sessions twice weekly for 24 wk. Changes in dependent variables over time were analyzed using repeated-measures ANOVA. Significance was accepted at P ≤ 0.05.

Results: There were no group–time effects for body composition, BMD, or blood biomarkers. Main effects were observed for left femoral neck (0.883 ± 0.138 to 0.870 ± 0.131 g·cm−2) and left forearm (0.465 ± 0.078 to 0.457 ± 0.069 g·cm−2) BMD. The FIT group improved upper body strength (73.2 ± 18.1 to 83.2 ± 22.3 kg), whereas the yin yoga group did not (59.8 ± 14.8 to 59.3 ± 15.6 kg). Main time effects were observed for peak isokinetic knee extension and flexion at all speeds with an average improvement of 13.2% and 16.2%, respectively.

Conclusion: Both FIT and yin yoga may be beneficial exercise modes for improving lower body strength, although only FIT improved upper body strength. Additional research is needed to examine the effectiveness of FIT programs of longer duration and/or higher intensity on body composition and BMD in BCS.

Introduction

Breast cancer is one of the most common forms of cancer among women in the United States.[1] Although outcomes for the disease have improved,[2] both the cancer and its treatments can result in long-term adverse effects, including gains in fat mass along with an accelerated loss in muscle and bone.[3,4] These changes can affect the long-term survival and quality of life of breast cancer survivors (BCS) as greater weight gain in cancer patients is associated with both the chance of relapse and death.[5–7] The combination of obesity and low muscle mass has been linked to lower physical function, poorer survival rates, and treatment toxicity compared with obese nonsarcopenic cancer survivors.[8–10] In addition, the concurrent loss in bone mineral density (BMD) places BCS at greater risk for osteoporosis and fractures.[11,12] Together these changes negatively affect quality of life and place BCS at greater risk for chronic disease, disability, and poor survival outcomes.

Weight gain commonly occurs with treatment, with a recent meta-analysis reporting an average weight increase of 2.7 kg among early-stage breast cancer patients who were treated with chemotherapy.[13] This noticeable weight gain is accompanied by an increase in body fat and decrease in muscle mass,[3,4] which can ultimately lead to decreased strength and physical function.[14,15] Furthermore, other side effects, including fatigue, neuropathy, and pain, serve as barriers for exercise participation in BCS,[16] which may also contribute to these negative body composition and functional changes.

Chemotherapy can also affect bone by inducing ovarian failure, leading to bone resorption as a result of estrogen loss.[17] Hopson et al.[18] reported a 6.6% and 4.1% loss in BMD at the lumbar spine and hip, respectively, along with a decrease in both the thickness and the area of cortical bone at the tibia after a 1-yr follow-up in premenopausal women undergoing chemotherapy for breast cancer. This accelerated bone loss continues after treatment completion, especially in BCS who experience ovarian failure, as Vehmanen et al.[19] reported significant bone loss 5 yr after treatment in those experiencing chemotherapy-induced ovarian failure. In addition, estrogen-reducing drugs can have adverse effects long after the completion of primary treatment as the estimated rate of bone loss from aromatase inhibitors at the lumbar spine and hip range from 1.7% to 5.8% per year.[20]

A meta-analysis in postmenopausal woman without cancer found that protocols combining resistance training with high-impact exercise were effective in improving hip and spine BMD.[21] Several studies have examined the effect of impact training protocols that have incorporated jumping or hopping movements on BMD in BCS. One 12-month study that included only aerobic-based high-impact movements was successful in maintaining BMD at the hip region in premenopausal, but not postmenopausal BCS.[22] To our knowledge, there are three studies that have incorporated a combination of resistance exercise and impact training involving jumping movements in breast cancer populations,[23–25] and all used the same resistance and impact training protocol. Overall results from these studies show that resistance training combined with impact training can attenuate losses in BMD and improve body composition in BCS. In these studies, resistance training was combined with one type of high-impact exercise that was performed with a weighted vest. Because unusual loading patterns have been found to be more effective than exercises where there is routine strain,[26] there is a need for more directed research involving interventions that incorporate resistance training along with several different impact exercises.

In addition, there is a need for innovative exercise training programs with high applicability that can be incorporated into a group exercise class with minimal equipment and without the use of weighted vests, which are often not feasible to use in a group exercise setting. Because 37.5% of BCS report that they prefer to exercise with one or two individuals or in a group setting,[27] a program that can be offered as a structured group exercise format that can be offered as part of a group exercise program may serve as a valuable alternative for those who may prefer a group exercise setting over the weight room. Therefore, more research is needed to determine whether a structured group exercise class that combines resistance and impact training is effective in improving body composition, bone, and strength outcomes in BCS as well as a feasible program to implement in a breast cancer population.

The purpose of this study was to examine the effects of 24 wk of supervised functional impact training (FIT), which combined resistance and high-impact exercises, on body composition, BMD, biomarkers for bone metabolism, and strength in BCS. In addition, because this was a new training protocol that has not been previously studied, feasibility of the program in terms of adherence, ability of BCS to tolerate the combined resistance and high-impact protocol, and adverse events related to FIT were also assessed to provide evidence for future implementation of this type of program. This program was compared with a nonexercise active control group receiving 24 wk of supervised yin yoga training that consisted of non–weight-bearing stretching and relaxation postures. We hypothesized that BCS participating in FIT would have improvements in body composition (increased fat loss and gains in lean mass), total and regional BMD, biomarkers for bone metabolism (increased bone-specific alkaline phosphatase [BAP] and decreased tartrate-resistant acid phosphatase [TRAP-5b]), and strength compared with those participating in yin yoga who would not experience improvements in these measures.

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