A protocol for a randomised controlled trial of the bone response to impact loading or resistance training in young women with lower than average bone mass: the OPTIMA-Ex trial

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.

Landing Impact Intensities for Jumping Exercises From the OPTIMA-Ex Trial in Trained and Untrained Women

ABSTRACT

Lambert, C, Beck, BR, and Weeks, BK. Landing impact intensities for jumping exercises from the OPTIMA-Ex trial in trained and untrained women. J Strength Cond Res 35(9): 2504-2510, 2021-High-intensity mechanical loads are required to elicit a positive adaptive bone response. Our aim was to quantify the mechanical loads of impact exercises used in each progressive stage of a bone-targeted exercise intervention (the OPTIMA-Ex trial) and to investigate differences in mechanical loads between untrained and trained subjects. A randomized repeated measures experimental design was used to quantify and compare the mechanical loads, including vertical ground reaction force (vGRF) and the rate of loading (RoL) of the landing phase, of all impact exercises applied in the OPTIMA-Ex trial and to determine the load intensity for each training stage of the impact intervention. Fifteen healthy young adult women aged 18-30 years (mean 23.1 ± 3.5 years) were recruited (5 trained and 10 untrained). Overall, vGRF was classified as high impact (>4 times body mass [BM]) for all 7 training stages (4.70 ± 1.89 to 6.79 ± 2.17 BM), whereas RoL ranged from 207.01 ± 175.09 to 371.52 ± 393.43 BM·s-1 across the stages. Furthermore, a significant time effect was observed between training stages for vGRF/BM (p = 0.001) and RoL (p < 0.001). Trained subjects exhibited greater impact loads than untrained subjects for activities at every training stage (p < 0.01). We found that impact activities at every stage of the OPTIMA-Ex trial not only met the GRF criteria for high intensity but also exhibited progressive increases in load for successive stages. Furthermore, trained subjects were capable of producing greater impact loads than untrained subjects.

Relationship between physical activity, lean body mass, and bone mass in the Mexican adult population

We evaluated the association between leisure-time physical activity (LTPA), bone mineral content (BMC), and lean mass (LM) in whole body (wb) and limbs of the Mexican adult population. Our results demonstrate that some types of LTPA with relatively high/medium impact on bones such as football, basketball, tennis, and weightlifting improve BMC and LM.

PURPOSE

To evaluate the effect of different kinds of leisure-time physical activity (LTPA) on bone mass values and its association with lean mass (LM) in the whole body (wb) and limbs of a large sample of Mexican men and premenopausal (pre-MP) women.

METHODS

We conducted a cross-sectional analysis of data from the Health Workers Cohort Study. Bone mineral content (BMC, kg), bone area (cm²), and LM (kg) were measured with DXA. The LTPA level and the "sedentary" condition were determined using a validated questionnaire adapted for the Mexican population. One-way ANOVA tests evaluated the differences in weight, height, body mass index, and wb, lower limb (ll) and upper limb (ul) BMC and LM between the active (those who engaged in LTPA) and sedentary group. Relationships between BMC and LM values were analyzed. Slopes of the curves and Z scores of LTPA groups with respect to the sedentary group were compared.

RESULTS

In men, both wb-BMC and ll-BMC were significantly higher in the groups performing basketball, football, tennis, weightlifting, and running, and all wb-LM, ll-LM, and ul-LM were higher in running, weightlifting, football, and basketball groups with respect to the sedentary group. Both the Z scores and the slopes of BMC-vs-LM relationships were higher than the controls, but only in the ll of male basketball and football players.

CONCLUSION

Our findings demonstrate that some types of LTPA with relatively high/medium impact on bones, such as football, basketball, tennis, and weightlifting, improve both BMC and LM compared to sedentary individuals. Finally, this relationship is stronger for the bones found in the legs and it seems that women are less sensitive to this effect, possibly due to hormonal, dietary, and pharmacological reasons.

Effect of Tai Chi exercise with the same frequency and different exercise duration on the bone mineral density of older women

BACKGROUND

This study compared the effect of Tai Chi with the same frequency and different session duration on the bone mineral density (BMD) of older women.

METHODS

Healthy older women aged 55-70 years were randomly divided into the short-time group (N.=17), long-time group (N.=18), and control group (N.=17). The BMD of L<inf>2-4</inf> and the proximal femur were measured at baseline and after 48 weeks of intervention.

RESULTS

From 0 to 48 weeks, the respective BMD values of L<inf>2-4</inf> and the femoral neck in the short-time and long-time groups increased by 8.8% and 7.5% (P<0.01) and 8.8% and 12.7% (P<0.01), while the BMD of the greater trochanter in the control group decreased by 3.0% (P<0.05). After 48 weeks, the BMD of L<inf>2-4</inf> and the femoral neck was greater in the short-time and long-time groups than the control group (P<0.001).

CONCLUSIONS

Tai Chi for 30 or 60 minutes five times weekly for 48 weeks improves the BMD of L<inf>2-4</inf> and the femoral neck in older women but does not affect the BMD of the greater trochanter and Ward's triangle. Increasing the exercise duration does not increase the effect of Tai Chi on BMD.

Regional changes in indices of bone strength of upper and lower limbs in response to high-intensity impact loading or high-intensity resistance training

It is well known that the bone response to physical activity is highly dependent on the nature of the loads imposed. Despite this, few direct comparisons of the effect of impact-style loading and resistance training on bone have been made. We therefore aimed to compare the effects of 10-month, twice-weekly, high-impact loading and 10-month, twice-weekly, high-intensity resistance training on indices of bone strength of both the upper and lower limbs of young adult women. Physically inactive, otherwise healthy, young adult women (18-30 years) with below average bone mass (T-score ≤ 0) were recruited as part of the OPTIMA-Ex trial. Testing included DXA- and pQCT-derived measures of bone mass and indices of bone strength and QUS-derived measures of bone quality of the dominant (D) and non-dominant (ND) upper (radius) and lower limbs (femoral neck, tibia, calcaneus). The present study examined those participants who completed the impact training (IT; n = 10) and resistance training (RT; n = 12) arms of the trial. Age differed between groups at baseline (IT = 23.2 ± 3.8 years, RT = 20.5 ± 1.8 years; p = 0.042). Compliance with the training programs did not differ (IT = 61.4 ± 15.1%, RT = 66.4 ± 11.2%, p = 0.381). Age and baseline differences in bone outcomes served as covariates for repeated measures and univariate ANCOVA conducted for dependent variables and percent change respectively. IT improved distal pQCT-derived bone mineral density (BMD) of the upper limb (ND radius: total BMD = 8.55 ± 2.26% versus 1.50 ± 2.04%, p = 0.040 and trabecular BMD = 1.86 ± 0.90% versus -1.30 ± 0.81%, p = 0.029) and lower limb (ND tibia trabecular BMD = 1.22 ± 0.55% versus -0.82 ± 0.50%, p = 0.017), more than RT. IT also improved upper limb bone strength index (BSI) (ND radius total BSI = 15.35 ± 2.83% versus 2.67 ± 2.55, p = 0.005) and lower limb BSI (D tibia total BSI = 5.16 ± 1.13% versus 0.37 ± 1.02%, p = 0.008; D tibia trabecular BSI = 3.93 ± 1.76% versus -2.84 ± 1.59, p = 0.014, ND tibia trabecular BSI = 3.57 ± 1.63% versus -3.15 ± 1.48%, p = 0.009) more than RT. Conversely, RT improved DXA-derived cortical volumetric BMD at the femoral neck more than IT (3.68 ± 1.99% versus -4.14 ± 2.20%, p = 0.021). Results suggest that IT and RT provide differing site-specific effects in both the upper and lower limbs, with superior bone responses observed at the distal segment from IT, while RT appeared to have greater effect on the shaft of the bone, on indices of bone-strength in young adult women.

Enjoyment and acceptability of different exercise modalities to improve bone health in young adult women

ISSUE ADDRESSED

Osteoporosis presents a serious public health issue and physical activity is recognised as the most effective modifiable risk factor for the condition. The reasons behind physical activity participation, however, are complex. We therefore aimed to explore the experiences related to a bone-targeted exercise intervention, determine enjoyment and acceptability of each exercise mode, and identify barriers and facilitators to osteogenic exercise for young adult women.

METHODS

The present study was conducted within the Osteoporosis Prevention Through Impact and Muscle-loading Approaches to Exercise (OPTIMA-Ex) trial, a three-arm RCT comparing musculoskeletal outcomes from two supervised, high-intensity, exercise programs (impact and resistance training) with an unsupervised low-intensity exercise control. A mixed-methods approach was used, including quality of life and physical activity enjoyment questionnaires and qualitative analysis of semi-structured interviews.

RESULTS

All groups had improvements in the 'mental health' domain of the quality of life measure; however, the two supervised exercise groups had greater levels of physical activity enjoyment. The qualitative analysis revealed that overall the trial activities were positively, yet the two supervised groups had 'richer' exercise experiences. Motivations for participation, barriers to physical activity and desired continuation of participation differed between all three groups.

CONCLUSIONS

Findings suggest that bone-targeted exercise interventions for young adult women must address perceived time demands and environmental barriers to participation in order to maximise compliance and adherence. SO WHAT?: As physical activity is the most effective lifestyle strategy to improve bone health and young adulthood an important window for its augmentation, increasing convenience, accessibility and understanding of osteoporosis preventative behaviours in this demographic is vital.