High-Intensity Weight Training Is Safe and Effective in Osteoporosis

Nancy A Melville

October 04, 2017

A novel, twice-weekly, high-intensity resistance training scheme shows significant gains in bone-mineral density (BMD) and strength in postmenopausal women with low bone mass, without the safety issues that are of particular concern in that population.

"Importantly, no fractures or major adverse events were observed, suggesting high-intensity resistance and impact training (HIRIT) may be safe for postmenopausal women with low to very low bone mass, despite previous safety concerns," report Steven L Watson, of Griffith University, in Queensland, Australia, and colleagues in the Journal of Bone and Mineral Research.

"The evidence from (this) trial…justifies a quantum change in attitude in this regard," they add.

Concerns about fracture risk associated with weight training in people with low BMD have resulted in osteoporosis exercise guidelines typically recommending only routines of moderate intensity. Not surprisingly, improvements in BMD in such exercise programs are typically lackluster.

With some shorter studies showing encouraging improvements and safety with higher-intensity interventions, however, the researchers developed a novel, bone-targeted, HIRIT program with the specific aim of improving femoral neck and lumbar spine BMD in postmenopausal women with low to very low bone mass.

With the widely held assumption that high-intensity resistance training represents a risk to people with low BMD, research in the area is scant, underscoring the importance of the new findings, senior author Belinda R Beck, PhD, director of the Bone Clinic, in Queensland, Australia, told Medscape Medical News.

"What we have done is essentially 'bitten the bullet' to find out if the conventional assumption was correct by taking the risk of testing it under tightly controlled randomized controlled trial conditions, and it turns out the assumption was not correct," said Dr Beck, who is also a professor with the Menzies Health Institute, Griffith University.

An important caveat, she noted, is that supervision and administration of the program by trained personnel is key: "This is not a program to simply be handed to a person with osteoporosis and told to go to a gym."

"This is why we established the Bone Clinic, where we have translated the research findings into practice and continue to conduct research."

LIFTMOR: HIRIT Shows Improvement in Bone Mass and Muscle Strength

In the Lifting Intervention for Training Muscle and Osteoporosis Rehabilitation (LIFTMOR) trial, 101 postmenopausal women with a mean age of 65 and low bone mass (T-score < -1.0) were enrolled.

The women were randomized to either 8 months of the intervention (n = 49), consisting of twice-weekly, 30-minute supervised HIRIT or a control group receiving a home-based low-intensity program (n = 52).

The HIRIT intervention was initiated gradually in small groups with a maximum of eight participants, with the first month consisting of body weight and low-load exercise variants and a focus on progressive learning.

For the remainder of the study, the exercise sessions involved five sets of five repetitions, including resistance exercises of dead lift, overhead press, and back squat, maintaining an intensity of greater than 80% to 85% of one repetition maximum. Impact-loading exercises included jumping chin-ups with drop landings.

After the 8-month program, women in the intervention groups showed significantly greater improvements in key bone measures than the control group, including changes in lumbar spine BMD (+2.9% vs –1.2%, P < .001), femoral neck BMD (+0.3% vs –1.9%, = .004), and femoral neck cortical thickness (+13.6% vs +6.3%, = .014).

The intervention group also showed greater improvements in height (+0.2 cm vs –0.2 cm, = .004), and all functional performance measures (P < .001).

There was only one adverse event reported — a minor lower-back spasm in the HIRIT group. Compliance was meanwhile high in both groups, with dropout rates of 12% in the HIRIT group and 17% for the control group.

While the intervention arm was not sufficiently powered to examine the important issue of falls, improvements were nevertheless seen in measures associated in other studies with a reduction of the risk of falling, such as muscle strength and functional and neuromuscular performance, the authors note.

"Improvements in those functional performance scores therefore suggest HIRIT may not only reduce the risk of fracture by enhancing parameters of bone strength but by preventing falls in postmenopausal women with low bone mass," they stress.

They add that the study's design, as well as findings, are new.

"To our knowledge, there has been no trial of adequate size and/or duration to determine the efficacy of high-intensity loading to improve bone mass in postmenopausal women with low to very low bone mass; thus, our findings are novel.

"Our observed improvements in BMD surpass previous reports from reputable exercise interventions, an observation that could be considered intuitive in light of the well-known positive relationship between load magnitude and bone adaptation."

Key to Safety Is Gradual Introduction of Exercises, Rest Days

Key to safety and efficacy of the program is the gradual introduction of the exercises, including the need for rest days between sessions, stressed Dr Beck.

"Heavy lifting requires significant recovery, so I would always recommend at least 1 day of rest between trainings," she said, adding, "The people with poorest bones respond the most but will probably require the most rest days to begin with."

Comparing the twice-weekly HIRIT program with most exercise advice for osteoporosis — which generally recommends activities on a 5-day-per-week basis — Dr Beck noted the latter "are more focused on falls prevention and employ a more conservative program, which will not notably improve bone mass.

Meanwhile, some of the HIRIT program improvements in bone mass in fact exceeded expectations.

"To be honest, I was surprised we would build so much bone at the spine — with some increases as much as 12%, because previous exercise interventions have not been very effective, but our high-intensity approach was key," Dr Beck said.

In contrast, changes in hip BMD were unexpectedly not as impressive as the spine.

"Given the type of loading we were doing, we would have thought the hip would respond more markedly," she said. "We are currently doing some biomechanical analyses to examine exactly the nature of the loads experienced at the femoral neck to try to understand the BMD response."

Of note, 3D analyses of the proximal femur suggested the cortex of the femoral neck thickened in the absence of BMD gains, which is highly significant in terms of improving strength, Dr Beck observed.

"It is possible that bone geometry of the femoral neck changes in an advantageous way in response to our program, rather than BMD."

The improvements seen in height were also unexpected.

"That was certainly a pleasant surprise, partly because many naysayers of heavy lifting for osteoporosis think it will cause compression fractures in the spine; however, there was absolutely no evidence of that in our trial," she noted.

She acknowledged that the HIRIT program's need for training and supervision is perhaps its most notable limitation, but the findings indicate that the effort is worthwhile.

"The reality is, if you want to grow bone, this is the form of exercise you need to do. Doing a more conservative form of exercise so you can roll it out for unsupervised exercise training might be great for the heart, but it will not improve bone."

The authors have no relevant financial relationships.

J Bone Miner Res. Published October 4, 2017. Abstract

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