Bone-specific physical activity questionnaire-derived skeletal loading score predicts bone geometry, density, and strength indices: a cross-sectional study

INTRODUCTION

The bone-specific physical activity questionnaire (BPAQ) provides a bone-relevant index of physical activity participation according to the mechanical loads experienced across the life span.

MATERIALS AND METHODS

We aimed to examine relationships between historical bone-relevant physical activity and pQCT-derived parameters of bone strength. We recruited 532 healthy volunteers (277 males, 255 females) across a broad age range (4-97 years). Peripheral quantitative computed tomography (XCT-3000, Stratec, Germany) was used to examine volumetric bone density, area, and strength indices of the non-dominant tibia and radius. Exercise loading history from birth was determined using the past BPAQ (pBPAQ) score. Pearson correlation analysis was used to examine relationships between pBPAQ scores and pQCT parameters.

RESULTS

Independent of sex, pBPAQ scores were associated with total density at the 38% and 66% tibial sites and the 66% radial site (r = 0.145-0.261, p ˂ 0.05), total area at the 38% tibial site and 4% and 66% radial sites (r = 0.129-0.156, p ˂ 0.05), and strength indices at all measured sites (r = 0.123-0.234, p < 0.05).

CONCLUSION

We conclude that, independent of sex, historical bone-relevant physical activity is associated with pQCT-derived indices of bone strength, indicating that pBPAQ captures the characteristics of bone loading history that are likely to be relevant adaptive stimuli. A larger sample is required to examine the influence of age on this relationship.

High-Intensity Exercise and Geometric Indices of Hip Bone Strength in Postmenopausal Women on or off Bone Medication: The MEDEX-OP Randomised Controlled Trial

To compare the effects of high-intensity resistance and impact training (HiRIT) to low-intensity, Pilates-based exercise (LiPBE) on proximal femur geometry and explore the influence of antiresorptive medication on those effects. Postmenopausal women with low bone mass, on or off antiresorptive bone medications were randomly allocated, stratified on medication intake, to eight months of twice-weekly, supervised HiRIT (Onero™) or LiPBE (Buff Bones®). 3D hip software was used to analyse proximal femur DXA scans. Outcomes included femoral neck (FN) and total hip (TH), volumetric (e.g. vBMC, vBMD) and geometric (e.g. cortical thickness, cross-sectional area [CSA], section modulus [Z]) indices of bone strength. Data were analysed using analysis of variance. Scans of 102 women were examined: LiPBE, 43; HiRIT, 37; LiPBE-med, 11; HiRIT-med, 11. HiRIT improved TH trabecular vBMC and vBMD (3.1 ± 1.1% versus - 1.2 ± 1.2%, p = 0.008; and 1.5 ± 1.0% versus - 1.6 ± 1.2%, p = 0.042, respectively) and FN and TH total vBMC (2.0 ± 0.8% versus - 0.2 ± 0.7%, p = 0.032; and 0.7 ± 0.4% versus - 0.8 ± 0.6%, p = 0.032, respectively), compared to losses in LiPBE. HiRIT also increased Z while LiPBE did not (p = 0.035). The combination of HiRIT and medication achieved greater improvements in FN total and trabecular vBMD, total BMC, CSA and Z than HiRIT alone. HiRIT improved geometric parameters of proximal femur strength, while LiPBE exercise was largely ineffective. Medication may enhance some HiRIT effects. Findings suggest reduced hip fracture risk in response to HiRIT.Trial registration number ACTRN12617001511325.

A Comparison of Bone-Targeted Exercise With and Without Antiresorptive Bone Medication to Reduce Indices of Fracture Risk in Postmenopausal Women With Low Bone Mass: The MEDEX-OP Randomized Controlled Trial

The goal of the MEDEX-OP trial was to compare the efficacy of a known effective high-intensity resistance and impact training (HiRIT) with a low-intensity exercise control (Buff Bones® [BB]), alone or in combination with antiresorptive bone medication, on indices of fracture risk (bone mass, body composition, muscle strength, functional performance), compliance, and safety. Primary study outcomes were 8-month change in lumbar spine (LS) and total hip (TH) bone mineral density (BMD). Healthy postmenopausal women with low bone mass (T-score ≤ -1.0) on or off stable doses (≥12 months) of antiresorptive medication were recruited. A total of 115 women (aged 63.6 ± 0.7 years; body mass index [BMI] 25.5 kg/m² ; femoral neck [FN] T-score -1.8 ± 0.1) were randomly allocated to 8-month, twice-weekly, 40-minute HiRIT (5 sets of 5 repetitions, >80% to 85% 1 repetition maximum) or BB (low-intensity, Pilates-based training), stratified by medication intake, resulting in four groups: HiRIT (n = 42), BB (n = 44), HiRIT-med (n = 15), BB-med (n = 14). HiRIT improved LS BMD (1.9 ± 0.3% versus 0.1 ± 0.4%, p < 0.001) and stature (0.2 ± 0.1 cm versus -0.0 ± 0.1 cm, p = 0.004) more than BB. Both programs improved functional performance, but HiRIT effects were larger for leg and back muscle strength and the five times sit-to-stand test (p < 0.05). There was a positive relationship between maximum weight lifted and changes in LS BMD and muscle strength in the HiRIT groups. Exploratory analyses suggest antiresorptive medication may enhance exercise efficacy at the proximal femur and lumbar spine. Exercise compliance was good (82.4 ± 1.3%) and both programs were well tolerated (7 adverse events: HiRIT 4; BB 3). HiRIT improved indices of fracture risk significantly more than Buff Bones®. More trials combining bone medication and bone-targeted exercise are needed. © 2021 American Society for Bone and Mineral Research (ASBMR).

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.

Exploring thoracic kyphosis and incident fracture from vertebral morphology with high-intensity exercise in middle-aged and older men with osteopenia and osteoporosis: a secondary analysis of the LIFTMOR-M trial

Our aim was to explore change in kyphosis and vertebral fracture incidence following 8 months of high-intensity resistance and impact training (HiRIT) or machine-based isometric axial compression (IAC) training in men with osteopenia and osteoporosis. HiRIT and IAC improved posture. HiRIT participants did not experience progression or incident vertebral fracture. IAC participants did experience progression and incident vertebral fracture.

INTRODUCTION

The Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men (LIFTMOR-M) trial examined efficacy and safety of an eight-month, supervised, high-intensity progressive resistance and impact training (HiRIT) program compared with machine-based isometric axial compression (IAC) training in middle-aged and older men with low areal bone mineral density (aBMD). The primary purpose of the current work was to explore change in thoracic kyphosis and incident fracture from vertebral morphology following eight-months of HiRIT or IAC training. The secondary purpose was to explore change in clinical kyphosis measures for HiRIT, IAC and a non-randomized, matched control group.

METHODS

Men (≥ 45 yrs), with low aBMD, were recruited and randomized to HiRIT or IAC, or designated control. Clinical measures of thoracic kyphosis with inclinometry were determined. Cobb angle of kyphosis and vertebral fracture assessment using the Genant semi-quantitative method were determined from lateral thoracolumbar DXA (Medix DR, Medilink, France). Per-protocol (n = 40) and intention-to-treat (n = 93) analyses were conducted.

RESULTS

Forty participants (HiRIT n = 20, IAC n = 20; 66.1 ± 7.8 yrs.; lumbar spine T-score - 0.1 ± 0.8; femoral neck T-score - 1.5 ± 0.5) underwent clinical kyphosis measures and thoracolumbar DXA at baseline and follow-up. No between-group differences were detected in kyphosis change, however, within-group improvements in neutral (HiRIT - 2.3 ± 0.8°; IAC - 2.5 ± 0.8°) and 'standing tall' (HiRIT - 2.4 ± 0.8°; IAC - 2.0 ± 0.8°) postures were observed (p < 0.05). HiRIT improved Cobb angle (- 3.5 ± 1.5°, p = 0.027) from baseline. Over the 8 months, no incident vertebral fractures nor progression of prevalent vertebral fractures occurred for HiRIT participants. Five incident fractures of thoracic vertebrae occurred for IAC and one wedge fracture progressed. Ninety-three participants underwent clinical kyphosis measures at both time-points (HiRIT n = 34, IAC n = 33, control n = 26). HiRIT exhibited a reduction in 'standing tall' kyphosis compared to control (- 2.3 ± 0.6° versus 1.4 ± 0.7°, p < 0.05), but no other between-group differences were detected.

CONCLUSIONS

Although there was no difference in change between intervention groups, thoracic kyphosis appeared to improve in both HiRIT and IAC with exercise exposure. HiRIT improved 'standing tall' posture in comparison to usual activities. HiRIT was not associated with vertebral fracture progression or incident vertebral fracture, but for some IAC participants there was evidence of progression of vertebral fracture severity and incident vertebral fractures, in our small sample. Larger trials are required to confirm the observations of the current work, which was exploratory in nature.

The effect of exercise intensity on bone in postmenopausal women (part 2): A meta-analysis

BACKGROUND

Previous reviews have concluded that exercise has only modest effects on bone mineral density (BMD) in postmenopausal women. Despite the well-recognized strong positive relationship between load magnitude and bone response observed from animal research, the majority of human trials have examined the effects of only low to moderate intensity exercise on bone. We speculated that meta-analysing according to intensity may reveal a more potent exercise effect at higher intensity.

OBJECTIVES

To determine the effects of low, moderate and high intensity exercise on BMD at the spine and hip in postmenopausal women.

METHODS

Electronic databases and reference lists were searched for RCTs that examined the effect of exercise compared to control on DXA-derived lumbar spine, femoral neck or total hip BMD in healthy postmenopausal women. Interventions were classified as low, moderate or high intensity and pooled based on classification. Mean differences (MD) were calculated using random effects models and a risk of bias analysis was undertaken. To determine the effect of different exercise types (resistance and impact training) on BMD outcomes, subgroup analyses for all intensity categories and outcomes were conducted. Separate meta-analyses were undertaken to examine the influence of adding exercise to a bone medication intervention and to examine exercise effects on fracture risk.

RESULTS

Fifty-three trials, testing 63 interventions (19 low, 40 moderate, 4 high intensity) were included. At the lumbar spine, high intensity exercise yielded greater BMD effects (MD = 0.031 g/cm² 95% CI [0.012, 0.049], p = 0.002) than moderate (MD = 0.012 g/cm² 95% CI [0.008, 0.017], p < 0.001) and low intensity (MD = 0.010 g/cm² 95% CI [0.005, 0.015], p < 0.001). Low and moderate intensity exercise was equally effective at the femoral neck (low: 0.011 g/cm² 95% CI [0.006, 0.016], p < 0.001; moderate: 0.011 g/cm² 95% CI [0.007, 0.015], p < 0.001), but no effect of high-intensity exercise was observed. Moderate intensity exercise increased total hip BMD (0.008 g/cm² 95% CI [0.004, 0.012], p < 0.001), but low intensity did not. There were insufficient data to meta-analyse the effect of high intensity exercise at the total hip. Resistance training, potentially in combination with impact training, appears to be the most effective osteogenic stimulus at the spine and hip. Findings from meta-regression analyses were not informative and no influence of exercise on medication efficacy was observed. Risk of bias was mainly low or unclear due to insufficient information reported.

CONCLUSION

High intensity exercise is a more effective stimulus for lumbar spine BMD than low or moderate intensity, but not femoral neck BMD, however, the latter finding may be due to lack of power. While data from high-intensity exercise interventions are limited, the current comprehensive meta-analysis demonstrates the same positive relationship between load magnitude and bone response in humans that is observed in animal research. Findings have implications for optimal exercise prescription for osteoporosis in postmenopausal women.

STUDY REGISTRATION

Registered on PROSPERO (CRD42018117254).

The effect of exercise intensity on bone in postmenopausal women (part 1): A systematic review

BACKGROUND

Previous systematic reviews and meta-analyses of exercise effects on bone have reported null or modest effect sizes. While animal research has determined that a strong positive relationship exists between load magnitude/intensity and bone adaptation, nevertheless many human exercise interventions have been applied at low intensity. Meta-analytic pooling of exercise interventions irrespective of intensity dilutes the ability to detect efficacy of any one training regimen. Parsing out efficacy of low, moderate and high intensity exercise interventions will assist the determination of optimal exercise prescription for bone.

OBJECTIVES

First, to summarise and critically evaluate existing evidence of exercise effect on bone mass, bone structure and bone turnover markers (BTMs) in healthy postmenopausal women. Second, to examine the influence of intensity on bone response to exercise.

METHODS

Electronic databases (Embase, Scopus, CINAHL Plus, SPORTDiscus), database platforms (PubMed, Cochrane CENTRAL, ProQuest Central, Web of Science) and reference lists of included studies were searched for controlled trials and randomised controlled trials that described the effect of any exercise intervention compared to control on bone mass, bone structure or BTMs in healthy postmenopausal women. Fracture incidence was included as an exploratory endpoint. Data was extracted and weighed against the results of a comprehensive risk of bias analysis.

RESULTS

One hundred trials were included, investigating a total of 120 exercise interventions. Of those, 57 interventions were low intensity, 57 were moderate, and six were high intensity. On balance, low intensity exercise was not an effective stimulus to increase bone mass. Higher quality evidence suggests moderate to high intensity interventions, particularly those that combined high intensity resistance and impact training, were most beneficial for bone mass. Only high intensity exercise appears to improve structural parameters of bone strength, however, data are limited. Only low and moderate intensity interventions have measured BTMs and no notable benefits have been observed. The quality of trials varied greatly, and risk of bias determinations were frequently limited by insufficiently reported detail.

CONCLUSION

Heterogeneity in both study quality and outcomes limits the ability to draw strong conclusions from this comprehensive systematic review of RCT and CT reports. Nevertheless, there is a tendency in the higher quality data to indicate exercise intensity is positively related to the adaptive bone response. Part 2 of this review series reports a meta-analysis of the RCT data in order to draw quantitative conclusions from the higher quality trials.

STUDY REGISTRATION

Registered on PROSPERO (CRD42018117254).

A Comparison of Bone-Targeted Exercise Strategies to Reduce Fracture Risk in Middle-Aged and Older Men with Osteopenia and Osteoporosis: LIFTMOR-M Semi-Randomized Controlled Trial

The Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men (LIFTMOR-M) trial examined efficacy and safety of two novel exercise programs in older men with low BMD. Men with low hip and/or LS BMD were randomized to high-intensity progressive resistance and impact training (HiRIT) or machine-based isometric axial compression (IAC) and compared to a nonrandomized matched control (CON). Outcomes included: hip and LS BMD; calcaneal ultrasound parameters; anthropometry; body composition; function (timed up-and-go [TUG], five-times sit-to-stand [FTSTS]); back extensor strength (BES); leg extensor strength (LES); compliance and adverse events. Ninety-three men (67.1 ± 7.5 years; 82.1 ± 11.6 kg; 175.2 ± 6.7 cm; FN T-score -1.6 ± 0.6) were randomized to HiRIT (n = 34) or IAC (n = 33), or allocated to CON (n = 26). HiRIT improved trochanteric BMD (2.8 ± 0.8%; -0.1 ± 0.9%, p = .024), LS BMD (4.1 ± 0.7%; 0.9 ± 0.8%, p = .003), BUA (2.2 ± 0.7%; -0.8 ± 0.9%, p = .009), stiffness index (1.6 ± 0.9%; -2.0 ± 1.1%, p = .011), lean mass (1.5 ± 0.8%; -2.4 ± 0.9%, p = .002), TUG, FTSTS, BES, and LES (p < .05) compared with CON. IAC improved lean mass (0.8 ± 0.8%; -2.4 ± 0.9%, p = .013) and FTSTS (-4.5 ± 1.6%; 7.5 ± 2.0%, p < .001) compared with CON. HiRIT improved LS BMD (4.1 ± 0.7%; 2.0 ± 0.7%, p = .039), stiffness index (1.6 ± 0.9%; -1.3 ± 0.9%, p = .025), and FTSTS (-10.7 ± 1.6%; -4.5 ± 1.7%, p = .010) compared with IAC. Exercise compliance was high (HiRIT 77.8 ± 16.6%; IAC 78.5 ± 14.8%, p = .872). There were five minor adverse events (HiRIT, 2; IAC, 3). HiRIT was well-tolerated and improved bone, function and fracture risk more than CON or IAC. © 2020 American Society for Bone and Mineral Research.

Effects of supervised high-intensity resistance and impact training or machine-based isometric training on regional bone geometry and strength in middle-aged and older men with low bone mass: The LIFTMOR-M semi-randomised controlled trial

INTRODUCTION

Few data exist on the effects of bone-targeted exercise on geometric and biomechanical indices of bone strength in men. The Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men (LIFTMOR-M) trial was designed to compare the efficacy and safety of two novel, supervised, twice-weekly, high-intensity exercise programs in middle-aged and older men with osteopenia and osteoporosis on musculoskeletal health and risk factors related to falls and fractures. The current report includes secondary outcomes of the LIFTMOR-M exercise intervention trial.

PURPOSE

Our goal was to determine the effects of two supervised, twice-weekly, high-intensity exercise programs on bone geometry and strength of the proximal femur, and distal and proximal sites of the tibia and radius in middle-aged and older men with osteopenia and osteoporosis.

METHODS

Generally-healthy men (≥45 years), with low lumbar spine (LS) and/or proximal femur areal bone mineral density (aBMD), were recruited from the community. Eligible participants were randomised to either eight months of twice-weekly supervised high-intensity progressive resistance and impact training (HiRIT) or supervised machine-based isometric axial compression (IAC) exercise training. Intervention group outcomes were compared at baseline and eight months with a matched but non-randomised control group (CON) who self-selected to usual activities. DXA scans (Medix DR, Medilink, France) of the skeletally non-dominant proximal femur were analysed using 3D hip software (DMS Group, France) to derive femoral neck (FN) and total hip (TH) bone mineral content (BMC), volume, and volumetric bone mineral density (vBMD) for total, trabecular and cortical bone compartments. Total FN cortical thickness was determined as well as anterior, posterior, lateral and medial subregions. pQCT scans (XCT-3000, Stratec, Germany) of the 4 and 38% sites of the tibia, and 4 and 66% sites of the radius were conducted to determine a range of geometric and bone structural strength indices. Intervention effects were examined using univariate ANCOVA of percent change, and repeated measures ANCOVA of raw baseline and follow-up data, controlling for initial values, using intention-to-treat and per-protocol approaches.

RESULTS

Ninety-three men (67.1 ± 7.5 yrs, 175.2 ± 6.7 cm, 82.1 ± 11.6 kg, 26.7 ± 3.5 kg/m²) with lower than average aBMD (LS T-score -0.06 ± 1.04, FN T-score -1.58 ± 0.58, TH T-score -1.00 ± 0.58) were recruited, and designated CON (n = 26) or randomised to HiRIT (n = 34) or IAC (n = 33). Compliance to the supervised exercise programs did not differ (HiRIT 77.8 ± 16.6% versus IAC 78.5 ± 14.8%, p = 0.872). HiRIT improved medial FN cortical thickness compared with CON (5.6 ± 1.7% versus -0.1 ± 1.9%, p = 0.028) and IAC (5.6 ± 1.7% versus 0.7 ± 1.7%, p = 0.044). Distal tibia total BMC, vBMD, area and bone strength index, and trabecular BMC and bone strength index all declined for CON compared with maintenance for both HiRIT and IAC (all p < 0.05). HiRIT maintained distal tibia trabecular area compared with a loss in CON (0.2 ± 0.5% versus -1.6 ± 0.5%, p = 0.013). HiRIT and IAC maintained distal radius total BMC compared with loss in CON (-0.1 ± 0.7% versus -3.7 ± 0.8%, p = 0.001; 1.3 ± 0.7% versus -3.7 ± 0.8%, p < 0.001, respectively). HiRIT and IAC maintained distal radius total bone strength index compared with loss in CON (1.4 ± 1.4% versus -6.0 ± 1.6%, p = 0.001; 0.2 ± 1.3% versus -6.0 ± 1.6%, p = 0.004, respectively). HiRIT reduced proximal radius cortical area compared with CON (-3.1 ± 1.0% versus 1.1 ± 1.2%, p = 0.011) and IAC (-3.1 ± 1.0% versus -0.2 ± 1.0%, p = 0.042). No between-group differences were detected in any pQCT-derived bone outcome at the diaphyseal tibia 38% site.

CONCLUSION

Findings indicate that supervised HiRIT provides a positive stimulus to cortical bone at the medial FN compared with supervised IAC exercise, and both HiRIT and IAC preserve bone strength at the distal tibia and distal radius. These effects may translate into a reduced risk of lower and upper extremity fracture in middle-aged and older men with low bone mass.

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.

Characterisation of peripheral bone mineral density in youth at risk of secondary osteoporosis - a preliminary insight

OBJECTIVES

To describe peripheral long bone material and structural differences in youth at risk of secondary osteoporosis across disease-specific profiles.

METHODS

Upper- and lower limbs of children and adolescents were scanned at 4% distal and 66% mid-shaft sites using peripheral Quantitative Computed Tomography sub-categorised as (1) increased risk of secondary osteoporosis (neuromuscular disorders; chronic diseases; endocrine diseases; inborn errors of metabolism; iatrogenic conditions), (2) low motor competence and (3) non-affected controls.

RESULTS

Children with disease-specific profiles showed a range of bone deficits compared to the control group with these predominantly indicated for neuromuscular disorders, chronic diseases and low motor competence. Deficits between upper arm and lower leg long bone parameters were different for disease-specific profiles compared to the control group. Endocortical radius, muscle area, and mid-cortical ring density were not significantly different for any disease-specific profile compared to the control group for any bone sites.

CONCLUSIONS

Neuromuscular disorders, chronic diseases and low motor competence have a strong correlation to bone health for appendicular bone parameters in youth, suggesting a critical mechanical loading influence which may differ specific to disease profile. As mechanical loading effects are observed in regional bone analyses, targeted exercise interventions to improve bone strength should be implemented to examine if this is effective in reducing the risk of secondary osteoporosis in youth.

The influence of antiresorptive bone medication on the effect of high-intensity resistance and impact training on osteoporotic fracture risk in postmenopausal women with low bone mass: protocol for the MEDEX-OP randomised controlled trial

INTRODUCTION

Antiresorptive medications increase bone density and decrease vertebral fracture, while high-intensity resistance and impact training (HiRIT) increases balance, bone and muscle strength decreasing risk for falls and fractures. Medications are typically prescribed by doctors and exercise by exercise specialists, frequently in isolation.

OBJECTIVE

Our primary aim is to determine the effect of an 8-month HiRIT programme with or without osteoporosis medications on bone mineral density (BMD) of the spine and hip in postmenopausal women with low bone mass.

METHODS AND ANALYSIS

One hundred and sixty postmenopausal women with low bone mass will be recruited from the community to participate in an 8-month randomised controlled trial. Participants will be on stable doses of antiresorptive bone medication for at least 12 months (n=80) or have not taken bone medications for at least 12 months (n=80). Participants will be block randomised, stratified by medication intake, to twice-weekly 40-min supervised sessions of HiRIT or a low-intensity exercise programme (control). Primary outcomes include change in lumbar spine and total hip areal bone mineral density. Secondary outcomes include whole body, femoral neck and forearm BMD, proximal femur bone geometry and volumetric density, vertebral morphology, body composition, anthropometry, physical function, posture, rate of falls, osteoarthritis symptoms, pelvic floor health, quality of life, physical activity enjoyment, resting blood pressure, safety and compliance. All outcomes will be assessed at baseline and 8 months and intention-to-treat and per-protocol analyses will be conducted. Repeated measure analysis of covariance will be used to determine intervention effects on outcome measures, controlling for initial values, compliance and other variables found to differ between groups at baseline.

ETHICS AND DISSEMINATION

The study has been approved by Griffith University Human Research Ethics Committee (Ref: 2017/739). Results will be reported in peer-reviewed journals and at conferences.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12617001511325).

High-intensity exercise did not cause vertebral fractures and improves thoracic kyphosis in postmenopausal women with low to very low bone mass: the LIFTMOR trial

Our aim was to assess risk of vertebral fracture during high-intensity resistance and impact training (HiRIT) for postmenopausal women with low bone mass. HiRIT did not induce vertebral fracture, as evidenced by a reduction in kyphosis following 8 months of training and a lack of change in vertebral morphology.

INTRODUCTION

The LIFTMOR trial demonstrated a novel, HiRIT program notably improved bone mass in postmenopausal women with osteopenia and osteoporosis. While no clinical signs or symptoms of vertebral crush fracture were evident during the trial, anecdotal feedback suggests that concerns about safety of HiRIT in the osteoporosis demographic remain. The aim of the current work was to assess vertebral body morphology, Cobb angle, and clinical measures of thoracic kyphosis in participants in the LIFTMOR trial for evidence of vertebral fracture following 8 months of supervised HiRIT.

METHODS

Participants were randomized to either 8 months of 30-min, twice-weekly, supervised HiRIT or unsupervised, low-intensity, home-based exercise (CON). Lateral thoracolumbar DXA scans (Medix DR, Medilink, France) were performed at baseline and follow-up. Cobb angle was determined, and vertebral fracture identification was performed using the semiquantitative Genant method. Clinical kyphosis measurements were performed in relaxed standing (neutral posture) and standing tall using an inclinometer and a flexicurve.

RESULTS

The HiRIT group exhibited a reduction in inclinometer-determined standing tall thoracic kyphosis compared to CON (- 6.7 ± 8.2° vs - 1.6 ± 8.1°, p = 0.031). Both the HiRIT and CON groups exhibited within-group improvement in kyphosis in relaxed standing as measured by both inclinometer and flexicurve (p < 0.05). There were no changes in vertebral fracture classification in the HiRIT group post-intervention. A single, new, wedge deformity was observed for CON.

CONCLUSIONS

Supervised HiRIT was not associated with an increased risk of vertebral fracture in postmenopausal women with low bone mass. Indeed, a clinically relevant improvement in thoracic kyphosis was observed following 8 months of supervised HiRIT, further supporting its efficacy as an osteoporosis intervention for postmenopausal women with low to very low bone mass.

An examination of treadmill running familiarisation in barefoot and shod conditions in healthy men

Running on a treadmill is an activity that is novel to many people. Thus, a familiarisation period may be required before reliable and valid determinations of biomechanical parameters can be made. The current study investigated the time required for treadmill familiarisation under barefoot and shod running conditions. Twenty-six healthy men, who were inexperienced in treadmill running, were randomly allocated to run barefoot or shod for 20 minutes on a treadmill at a self-selected comfortable pace. Sagittal-plane kinematics for the ankle, knee and hip, and ground reaction force and spatio-temporal data were collected at two-minute intervals. For the barefoot condition, temporal differences were observed in peak hip flexion and peak knee flexion during swing. For the shod condition, temporal differences were observed for peak vertical ground reaction force. No temporal differences were observed after 8 minutes for either condition. Reliability analysis revealed high levels of consistency (ICC > 0.90) across all consecutive time-points for all dependent variables for both conditions after 8 minutes with the exception of maximal initial vertical ground reaction force loading rate. Participants in both barefoot and shod groups were therefore considered familiarised to treadmill running after 8 minutes.

Please Don't Move-Evaluating Motion Artifact From Peripheral Quantitative Computed Tomography Scans Using Textural Features

Most imaging methods, including peripheral quantitative computed tomography (pQCT), are susceptible to motion artifacts particularly in fidgety pediatric populations. Methods currently used to address motion artifact include manual screening (visual inspection) and objective assessments of the scans. However, previously reported objective methods either cannot be applied on the reconstructed image or have not been tested for distal bone sites. Therefore, the purpose of the present study was to develop and validate motion artifact classifiers to quantify motion artifact in pQCT scans. Whether textural features could provide adequate motion artifact classification performance in 2 adolescent datasets with pQCT scans from tibial and radial diaphyses and epiphyses was tested. The first dataset was split into training (66% of sample) and validation (33% of sample) datasets. Visual classification was used as the ground truth. Moderate to substantial classification performance (J48 classifier, kappa coefficients from 0.57 to 0.80) was observed in the validation dataset with the novel texture-based classifier. In applying the same classifier to the second cross-sectional dataset, a slight-to-fair (κ = 0.01-0.39) classification performance was observed. Overall, this novel textural analysis-based classifier provided a moderate-to-substantial classification of motion artifact when the classifier was specifically trained for the measurement device and population. Classification based on textural features may be used to prescreen obviously acceptable and unacceptable scans, with a subsequent human-operated visual classification of any remaining scans.

High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial

Optimal osteogenic mechanical loading requires the application of high-magnitude strains at high rates. High-intensity resistance and impact training (HiRIT) applies such loads but is not traditionally recommended for individuals with osteoporosis because of a perceived high risk of fracture. The purpose of the LIFTMOR trial was to determine the efficacy and to monitor adverse events of HiRIT to reduce parameters of risk for fracture in postmenopausal women with low bone mass. Postmenopausal women with low bone mass (T-score < -1.0, screened for conditions and medications that influence bone and physical function) were recruited and randomized to either 8 months of twice-weekly, 30-minute, supervised HiRIT (5 sets of 5 repetitions, >85% 1 repetition maximum) or a home-based, low-intensity exercise program (CON). Pre- and post-intervention testing included lumbar spine and proximal femur bone mineral density (BMD) and measures of functional performance (timed up-and-go, functional reach, 5 times sit-to-stand, back and leg strength). A total of 101 women (aged 65 ± 5 years, 161.8 ± 5.9 cm, 63.1 ± 10.4 kg) participated in the trial. HiRIT (n = 49) effects were superior to CON (n = 52) for lumbar spine (LS) BMD (2.9 ± 2.8% versus -1.2 ± 2.8%, p < 0.001), femoral neck (FN) BMD (0.3 ± 2.6% versus -1.9 ± 2.6%, p = 0.004), FN cortical thickness (13.6 ± 16.6% versus 6.3 ± 16.6%, p = 0.014), height (0.2 ± 0.5 cm versus -0.2 ± 0.5 cm, p = 0.004), and all functional performance measures (p < 0.001). Compliance was high (HiRIT 92 ± 11%; CON 85 ± 24%) in both groups, with only one adverse event reported (HiRIT: minor lower back spasm, 2/70 missed training sessions). Our novel, brief HiRIT program enhances indices of bone strength and functional performance in postmenopausal women with low bone mass. Contrary to current opinion, HiRIT was efficacious and induced no adverse events under highly supervised conditions for our sample of otherwise healthy postmenopausal women with low to very low bone mass. © 2017 American Society for Bone and Mineral Research.

Inter- and intra-tester reliability of the acute brain injury physiotherapy assessment (ABIPA) in patients with acquired brain injury

BACKGROUND

The Acute Brain Injury Physiotherapy Assessment (ABIPA) is a new outcome measure with face validity and sensitivity to change in the early stages of neuromotor recovery after acquired brain injury (ABI). Reliability of physiotherapists using the tool has not been established.

OBJECTIVE

Determine inter- and intra-tester reliability of physiotherapists using the ABIPA.

METHODS

An observational study using video-recorded assessments of patient performance (n = 7) was undertaken with two cohorts of physiotherapists: those receiving training (n = 23) and those provided with guidelines only (n = 7) to administer the ABIPA.

RESULTS

Across all physiotherapists (n = 30), inter-tester reliability was excellent (α ≥ 0.9) for total ABIPA score. All individual items, except trunk alignment in supine (α = 0.5), showed excellent or good internal consistency (α ≥ 0.7). For intra-tester reliability, substantial or perfect agreement was achieved for eight items (weighted Kappa K_w ≥ 0.6), moderate agreement for four items (K_w = 0.4-0.6) and three items achieved fair agreement (alignment head supine: K_w = 0.289; alignment trunk supine: Kw = 0.387 and tone left upper limb: K_w = 0.366).

CONCLUSION

Physiotherapists are highly consistent using the ABIPA but several items may need revision to improve intra-tester reliability.

Concurrent Validity and Reliability of a Linear Positional Transducer and an Accelerometer to Measure Punch Characteristics

Lambert, C, Beck, BR, and Weeks, BK. Concurrent validity and reliability of a linear positional transducer and an accelerometer to measure punch characteristics. J Strength Cond Res 32(3): 675-680, 2018-Punch speed is an important factor in the sport of boxing, and its measurement has important implications for monitoring training progression and outcomes. The aim of the current study was to establish the concurrent validity and reliability of a linear positional transducer and an accelerometer for the quantification of punch characteristics in untrained adults. Men and women aged 18-30 years with no previous boxing experience and no upper-limb musculoskeletal injuries were recruited. Participants performed 6 straight right punches; 3 at a self-determined 50% effort; and 3 at maximum effort. An accelerometer (Crossbow) and a linear positional transducer (GymAware) were used to examine peak velocity and acceleration of each punch. Validity was examined using Pearson's correlation analyses and by calculating mean bias and limits of agreement between measures from each device, whereas reliability was established using intraclass correlation coefficients (ICCs). Forty-four healthy young adults (28M and 16F; age 22.2 ± 2.9 years) participated. Moderate-to-strong positive associations were observed for both devices at 50% effort for velocity (r = 0.572-0.696) and acceleration (r = 0.867-0.921) and at maximum effort for velocity (r = 0.748-0.781) and acceleration (r = 0.897-0.946). High levels of reliability were observed with maximum punches for both devices (ICC = 0.922-0.981). Overall, moderate-strong measurement validity and reliability for punch speed was observed between the accelerometer and GymAware. Thus, the GymAware linear positional transducer is an acceptable measurement tool for the quantification of punch speed for straight punches in untrained adults.

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

INTRODUCTION

The aim of the Osteoporosis Prevention Through Impact and Muscle-loading Approaches to Exercise trial is to compare the bone response to two known osteogenic stimuli - impact loading exercise and resistance training. Specifically, we will examine the effect of a 10-month, twice-weekly, high-intensity impact loading exercise intervention and a 10-month, twice-weekly, high-intensity resistance training intervention on bone mass and strength at clinically important skeletal sites. The intervention groups will be compared against a home-based 'positive' control group. Safety and acceptability of each exercise modality will also be determined.

METHODS AND ANALYSIS

Sedentary otherwise healthy young women aged 18-30 years with bone mineral density (BMD) T-scores less than or equal to 0 at the hip and lumbar spine, screened for conditions and medications that influence bone and physical function, will be recruited. Eligible participants are randomised to 10-month, twice-weekly, either supervised high-intensity impact training, high-intensity resistance training or a home-based 'positive' control group. The primary outcome measure will be lumbar spine areal BMD, while secondary outcome measures will include: whole body, femoral neck and regional measures (upper and lower limb) of bone, muscle and fat; anthropometrics; muscle strength and power; quality of life and exercise safety, enjoyment and acceptability. All outcome measures will be conducted at baseline (T0) and 10 months (T10) and will be analysed according to the intention-to-treat principle and per protocol.

ETHICS AND DISSEMINATION

The study has been granted ethical approval from the Griffith University Human Research Ethics Committee (GU Ref: 2015/775). Standard scientific reporting practices will occur, including publication in peer-reviewed journals. Participant confidentiality will be maintained in all forms of reporting.

TRIAL REGISTRATION NUMBER

ACTRN12616001444471.

The LIFTMOR-M (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men) trial: protocol for a semirandomised controlled trial of supervised targeted exercise to reduce risk of osteoporotic fracture in older men with low bone mass

INTRODUCTION

The primary aim of the proposed study is to examine the efficacy of an 8-month supervised, high-intensity progressive resistance training and impact loading programme in comparison with a supervised machine-based isometric exercise training programme using the bioDensity system in older men with low bone mass. We will also determine the safety and acceptability of each exercise training mode. Intervention group responses will be compared with those of a self-selected, non-randomised control sample of sex-matched and age-matched men who will follow their usual lifestyle activities for 8 months.

METHODS AND ANALYSIS

Apparently healthy men over 50 years with low bone mass, screened for medical conditions and medications known to adversely affect bone health, will be recruited. Eligible participants will be randomly allocated to 8 months of either exercise programme with block randomisation based on presence or absence of osteoporosis medications. A twice-weekly, 30-minute, supervised exercise programme will be conducted for both groups. The primary outcome will be change in femoral neck areal bone mineral density determined by dual-energy X-ray absorptiometry (DXA). Secondary outcomes, assessed at baseline and 8 months, will include: DXA-derived whole-body, bilateral proximal femur and lumbar spine areal bone mineral density; proximal femur bone geometry and volumetric density extracted using three-dimensional hip analysis software; anthropometry; body composition; kyphosis; vertebral fracture assessment; physical function; safety (adverse events and injuries); and compliance. Intention-to-treat and per-protocol analyses will be conducted.

DISCUSSION

Whether a high-intensity, low-repetition progressive resistance training and impact loading programme or a machine-based isometric exercise programme can improve determinants of fracture risk, without causing injury, has not been examined in men. Determination of the efficacy, safety and acceptability of such programmes will facilitate formulation of future exercise guidelines for older men with low bone mass at risk of fragility fracture, a group who have previously been under-represented.

ETHICS AND DISSEMINATION

Participant confidentiality will be maintained with publication of results. The study has been granted ethical approval from the Griffith University Human Research Ethics Committee (Protocol number AHS/07/14/HREC).

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (www.anzctr.org.au)ANZCTR12616000344493; Pre-results.

Long bone robustness during growth: A cross-sectional pQCT examination of children and young adults aged 5-29years

Skeletal robustness (cross-section size relative to length) is associated with stress fractures in adults, and appears to explain the high incidence of distal radius fractures in adolescents. However, little is known about the ontogeny of long bone robustness during the first three decades of life. Therefore, we explored the ontogeny of tibial, fibular, ulnar and radial robustness in a cross-sectional sample of 5 to 29year-old volunteers of both sexes. Peripheral quantitative computed tomography (pQCT) was used to evaluate cross-sections of the leg (4%, 14%, 38% and 66%), and forearm (4%, and 66%) in N=432 individuals. Robustness was evaluated as the total bone area divided by bone length. Differences between age-groups, sexes, and age-group×sex interactions were evaluated with ANOVA with Tukey's post hocs where appropriate. Most bone sites exhibited more robust bones in men than women (P<0.001 to 0.02), and in older age-groups than younger (P<0.001). Sex×age-group interaction was observed at the 66% and 38% tibia sites with robustness increasing more with age in men than in women (P=0.006 to 0.042). Post-hoc analyses indicated no sex differences prior to 13years-of-age, and notable exceptions to increasing robustness with age at the 4% radial and 66% tibial sites, which exhibited reduced robustness in age groups close to peak height velocity. In conclusion, the present results suggest that very little sexual dimorphism in long bone robustness exists prior to puberty, and that divergence occurs primarily after cessation of longitudinal growth. A period of relative diaphyseal slenderness was identified at age-groups coinciding with the adolescent growth spurt, which may be related to the relatively high incidence of frank and stress fracture in adolescents.

Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children?

Objectives

The aim of the current study was to assess whether calcaneal broadband ultrasound attenuation (BUA) can predict whole body and regional dual-energy x-ray absorptiometry (DXA)-derived bone mass in healthy, Australian children and adolescents at different stages of maturity.

Methods

A total of 389 boys and girls across a wide age range (four to 18 years) volunteered to participate. The estimated age of peak height velocity (APHV) was used to classify children into pre-, peri-, and post-APHV groups. BUA was measured at the non-dominant heel with quantitative ultrasonometry (QUS) (Lunar Achilles Insight, GE), while bone mineral density (BMD) and bone mineral content (BMC) were examined at the femoral neck, lumbar spine and whole body (DXA, XR-800, Norland). Associations between BUA and DXA-derived measures were examined with Pearson correlations and linear regression. Participants were additionally ranked in quartiles for QUS and DXA measures in order to determine agreement in rankings.

Results

For the whole sample, BUA predicted 29% of the study population variance in whole body BMC and BMD, 23% to 24% of the study population variance in lumbar spine BMC and BMD, and 21% to 24% of the variance in femoral neck BMC and BMD (p < 0.001). BUA predictions were strongest for the most mature participants (pre-APHV R² = 0.03 to 0.19; peri-APHV R² = 0.05 to 0.17; post-APHV R² = 0.18 to 0.28) and marginally stronger for girls (R² = 0.25-0.32, p < 0.001) than for boys (R² = 0.21-0.27, p < 0.001). Agreement in quartile rankings between QUS and DXA measures of bone mass was generally poor (27.3% to 38.2%).

Conclusion

Calcaneal BUA has a weak to moderate relationship with DXA measurements of bone mass in children, and has a tendency to misclassify children on the basis of quartile rankings.

Cite this article: B. K. Weeks, R. Hirsch, R. C. Nogueira, B. R. Beck. Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children? Bone Joint Res 2016;5:538–543. DOI: 10.1302/2046-3758.511.BJR-2016-0116.R1.

Physical activity estimated by the bone-specific physical activity questionnaire is also associated with cardiovascular risk

The nature of physical activity that benefits bone is traditionally thought to differ from that benefiting cardiovascular health. Accordingly, exercise recommendations for improving bone health and cardiovascular health are largely incongruent. Our aim was to determine the associations between high-impact physical activity participation and both cardiovascular disease risk factors and bone mass. We recruited 94 men and women (age 34.0 ± 13.3 years) to undergo measures of cardiovascular disease risk (BMI, total cholesterol, fasting blood glucose, waist-to-hip ratio, and mean arterial pressure) and dual-energy X-ray absorptiometry (DXA XR-800, Norland) measures of bone mass (femoral neck, lumbar spine, and whole body BMD) and body composition (whole body lean mass and fat mass). Physical activity participation was estimated using the bone-specific physical activity questionnaire (BPAQ). Those in the upper tertile for current BPAQ score exhibited lower total cholesterol, waist-to-hip ratio, and mean arterial pressure than those in the lower tertiles (P < 0.05) with the relationship being mild-to-moderate (r = -0.49 to 0.29, P < 0.01). Those in the upper tertile for BPAQ score also had greater lumbar spine BMD than those in the lower tertile (P = 0.008), with BPAQ score predicting 6% of the variance in BMD (P = 0.02). We conclude that high-impact physical activity as captured by the BPAQ may be beneficial for both bone health and for attenuating cardiovascular disease risk.

Heavy resistance training is safe and improves bone, function, and stature in postmenopausal women with low to very low bone mass: novel early findings from the LIFTMOR trial

The aim of the LIFTMOR (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation) trial is to determine the safety and efficacy of brief, bone-targeted, high-intensity progressive resistance training (HiPRT) with impact loading for postmenopausal women with low bone mass. Preliminary findings indicate the LIFTMOR program is safe and effective.

INTRODUCTION

Despite a lack of notable efficacy, exercise guidelines for osteoporosis typically recommend moderate-intensity exercises, owing to a perceived risk of fracture from high-intensity loading. Indeed, safety concerns alone have prevented the well-recognised preferential response of bone tissue to high-intensity loads from being applied to those who stand to benefit the most. To progress from this therapeutic stalemate, a challenge to conventional wisdom was required. Our goal was to examine the safety and efficacy of HiPRT and impact loading for risk factors of osteoporotic fracture in postmenopausal women with low to very low bone mass.

METHODS

Participants have been randomised to either 8 months of twice-weekly 30-min supervised HiPRT and impact loading or a low-intensity home-based exercise program of the same duration and dose. Testing at baseline and follow-up has included anthropometry; bone, muscle, and fat mass; and functional performance.

RESULTS

Twenty-eight women (66.1 ± 4.8 years, mean lumbar spine T-score -2.15 ± 0.72) have completed the study. HiPRT and impact loading (n = 12) improved height (0.4 ± 0.2 cm vs -0.3 ± 0.1 cm, p = 0.003), femoral neck bone mineral density (0.3 ± 0.5 % vs -2.5 ± 0.8 %, p = 0.016), lumbar spine bone mineral density (1.6 ± 0.9 % vs -1.7 ± 0.6 %, p = 0.005), and functional performance (p < 0.05), compared to controls (n = 16). Compliance has been >87 %. There have been no injuries.

CONCLUSIONS

Brief supervised HiPRT with impact loading is a safe and effective exercise therapy for postmenopausal women with low to very low bone mass.

Effect of sex and fatigue on single leg squat kinematics in healthy young adults

Background

The single-leg squat (SLS) test is widely used in screening for musculoskeletal injury risk. Little is known, however, of lower limb, pelvis, and trunk kinematics of SLS performance or the effect of sex and fatigue. Our aim was to determine sex differences and the influence of fatigue on SLS kinematics in healthy young adults.

Methods

We recruited 60 healthy men and women between the ages of 20 and 40 years. Three-dimensional kinematic data was collected for SLSs with a ten-camera VICON motion analysis system (Oxford Metrics, UK) before and after a lower limb fatiguing exercise regime. One-way ANCOVA was used to make sex comparisons of kinematic parameters and repeated measures ANOVA was used to determine the effect of fatigue and the interaction with sex.

Results

30 men (25.6 ± 4.8 years) and 30 women (25.1 ± 3.8 years) volunteered to participate. Peak pelvic rotation (3.9 ± 4.1 vs. 7.7 ± 6.2 deg, P = 0.03), peak hip internal rotation (−1.8 ± 5.7 vs. 3.0 ± 7.3 deg, P = 0.02), hip adduction range (11.7 ± 4.8 vs. 18.3 ± 6.7 deg, P = 0.004), and hip rotation range (10.7 ± 3.9 vs. 13.0 ± 4.2 deg, P = 0.04) were smaller for men than for women. Likewise, distance of mediolateral knee motion (180 ± 51 vs. 227 ± 50 mm, P = 0.001) was shorter for men than for women. The kinematic response to fatigue was an increase in trunk flexion, lateral flexion and rotation, an increase in pelvic tilt, obliquity and rotation, and an increase in hip flexion and adduction range (P ≤0.05).

Conclusions

Sex differences in SLS kinematics appear to apply only at the hip, knee, and pelvis and not at the trunk. Fatiguing exercise, however, produces changes at the trunk and pelvis with little effect on the knee.

Characterisation of the Mechanical Loads and Metabolic Intensity of the CAPO Kids Exercise Intervention for Healthy Primary School Children

Sedentarism is associated with obesity and other chronic diseases at all ages. Increasing physical activity with in-school interventions, focusing on energy expenditure and bone loading reduces risk of a number of costly chronic diseases. The aim of the current study was to characterise the metabolic and musculoskeletal load intensity of the recent successful CAPO Kids exercise intervention. Pre and early pubertal children (10.4 ± 0.5 years old) from the CAPO Kids trial wore an armband sensor to estimate energy expenditure during a 10-minute CAPO Kids session. Eleven participants performed manoeuvres from the session on a force platform to determine vertical ground reaction forces. In total, 28 boys and 20 girls had armband measures and 11 boys and girls undertook GRF testing. The energy expenditure associated with the 10-minute session was 39.7 ± 9.3 kcal, with an average of 4 kcal·min-1. The intensity of physical activity was 'vigorous' to 'very vigorous' for 34% of the session. Vertical ground reaction forces of the CAPO Kids manoeuvres ranged from 1.3 ± 0.2 BW (cartwheels) to 5.4 ± 2.3 BW (360° jump). CAPO Kids generates adequate load intensity to stimulate positive health adaptations in both metabolic and musculoskeletal systems of pre and early pubertal children. Key pointsEnergy expenditure of a single bout of CAPO Kids yields 39.7±9.3 kcal and includes activities performed at a vigorous and very vigorous intensity.Mechanical loads associated with CAPO Kids surpass five times bodyweight and more than 140 bodyweights per second.CAPO Kids intervention represents a viable approach to stimulate musculoskeletal and metabolic adaptation in children.

Effects of bone-specific physical activity, gender and maturity on tibial cross-sectional bone material distribution: a cross-sectional pQCT comparison of children and young adults aged 5-29 years

Growth is the opportune time to modify bone accrual. While bone adaptation is known to be dependent on local loading and consequent deformations (strain) of bone, little is known about the effects of sex, and bone-specific physical activity on location-specific cross-sectional bone geometry during growth. To provide more insight we examined bone traits at different locations around tibial cross sections, and along the tibia between individuals who vary in terms of physical activity exposure, sex, and pubertal status. Data from 304 individuals aged 5-29 years (172 males, 132 females) were examined. Peripheral quantitative computed tomography (pQCT) was applied at 4%, 14%, 38%, and 66% of tibial length. Maturity was established by estimating age at peak height velocity (APHV). Loading history was quantified with the bone-specific physical activity questionnaire (BPAQ). Comparisons, adjusted for height, weight and age were made between sex, maturity, and BPAQ tertile groups. Few to no differences were observed between sexes or BPAQ tertiles prior to APHV, whereas marked sexual dimorphism and differences between BPAQ tertiles were observed after APHV. Cross-sectional location-specific differences between BPAQ tertiles were not evident prior to APHV, whereas clear location-specificity was observed after APHV. In conclusion, the skeletal benefits of physical activity are location-specific in the tibia. The present results indicate that the peri- or post-pubertal period is likely a more favourable window of opportunity for enhancing cross-sectional bone geometry than pre-puberty. Increased loading during the peri-pubertal period may enhance the bone of both sexes.

An in-school exercise intervention to enhance bone and reduce fat in girls: the CAPO Kids trial

The CAPO Kids trial was a 9-mo, controlled, school-based intervention to examine the effects of a novel, brief, high intensity exercise regime on indices of musculoskeletal and metabolic health in pre- and early-pubertal girls.

METHODS

A total of 151 pre- and early-pubertal girls (10.6±0.6years), recruited from two different schools consented to participate; 76 in the exercise group (EX) and 75 in the control group (CON). EX performed 10min bouts of thrice-weekly jumping plus capoeira (a Brazilian sport that combines martial art with dance), along with usual physical education (PE) activities. CON continued usual PE alone. Maturity, weight, height, waist circumference, resting heart rate and blood pressure, maximal vertical jump, and aerobic capacity were determined using standard clinical and field measures. Calcaneal broadband ultrasound attenuation (BUA) and stiffness index (SI) were determined from quantitative ultrasonometry. A subsample of children also underwent DXA and pQCT measures. Prior physical activity participation and daily calcium consumption were determined from validated instruments.

RESULTS

EX girls improved BUA more than CON (+4.5% vs. +1.4%, p=0.019). Resting heart rate (-7.2% vs. -1.8%, p<0.01), maximal vertical jump (+13.4% vs. -1.2%, p<0.001), estimated maximal oxygen consumption (+10.6% vs. +1.0%, p<0.001), and waist circumference (+2.7% vs. +5.6%, p<0.001) also improved more for EX than CON.

CONCLUSION

Ten minutes of high intensity exercise (capoeira and jumping) three times a week in the primary school setting enhances musculoskeletal and metabolic outcomes in pre- and early-pubertal girls without disrupting the academic schedule. The programme, amenable to broad-scale school implementation, would confer meaningful public health benefits.

Exercise to improve pediatric bone and fat: a systematic review and meta-analysis

PURPOSE

This study aimed to determine the effects of school-based, bone-focused exercise interventions on bone, fat, and lean mass in children by systematically reviewing and meta-analyzing the literature.

METHODS

Potentially relevant articles were identified by searching electronic databases. Abstracts were included if they described the effects of an in-school exercise intervention for children 5-17 yr old compared with controls and presented baseline and follow-up results for bone, fat, and lean measures. Identified studies were systematically reviewed for methodological quality. Meta-analyses were performed for whole body, lumbar spine, and femoral neck bone mineral content (BMC), fat, and lean mass.

RESULTS

Sixteen eligible trials were identified including eight randomized controlled trials, three clinical controlled trials, and five nonrandomized, nonmatched studies. The quality analysis revealed two studies had low, nine had medium, and five had a high risk of bias. Meta-analyses revealed a small positive effect of bone-targeted exercise on whole body BMC (standardized mean difference [SMD] = 0.483, 95% CI = 0.132-0.833), femoral neck BMC (SMD = 0.292, 95% CI = -0.022 to 0.607), lumbar spine BMC (SMD = 0.384, 95% CI = 0.193-0.575), fat mass (SMD = -0.248, 95% CI = -0.406 to -0.089), and lean mass (SMD = 0.159, 95% CI = -0.076 to 0.394).

CONCLUSIONS

Beneficial effects of school-based, bone-targeted exercise were observed for bone and fat, but not for lean mass. Excluding trials with high risk of bias strengthened that effect. Considerable study heterogeneity may have obscured effects on lean mass. The effects observed for bone and fat support the pursuit of brief, jumping-focused interventions to reduce fat as well as enhance musculoskeletal tissue in school age children.

Lower-limb kinematics of single-leg squat performance in young adults

PURPOSE

To determine the kinematic parameters that characterize good and poor single-leg squat (SLS) performance.

METHODS

A total of 22 healthy young adults free from musculoskeletal impairment were recruited for testing. For each SLS, both two-dimensional video and three-dimensional motion analysis data were collected. Pelvis, hip, and knee angles were calculated using a reliable and validated lower-limb (LL) biomechanical model. Two-dimensional video clips of SLSs were blindly assessed in random order by eight musculoskeletal physiotherapists using a 10-point ordinal scale. To facilitate between-group comparisons, SLS performances were stratified by tertiles corresponding to poor, intermediate, and good SLS performance.

RESULTS

Mean ratings of SLS performance assessed by physiotherapists were 8.3 (SD 0.5), 6.8 (SD 0.7), and 4.0 (SD 0.8) for good, intermediate, and poor squats, respectively. Three-dimensional analysis revealed that people whose SLS performance was assessed as poor exhibited increased hip adduction, reduced knee flexion, and increased medio-lateral displacement of the knee joint centre compared to those whose SLS performance was assessed as good (p≤0.05).

CONCLUSIONS

Overall, poor SLS performance is characterized by inadequate knee flexion and excessive frontal plane motion of the knee and hip. Future investigations of SLS performance should consider standardizing knee flexion angle to illuminate other influential kinematic parameters.

A video-based learning activity is effective for preparing physiotherapy students for practical examinations

OBJECTIVES

To examine a video-based learning activity for engaging physiotherapy students in preparation for practical examinations and determine student performance outcomes.

DESIGN

Multi-method employing qualitative and quantitative data collection procedures.

SETTING

Tertiary education facility on the Gold Coast, Queensland, Australia.

PARTICIPANTS

Physiotherapy students in their first year of a two-year graduate entry program.

MAIN OUTCOME MEASURES

Questionnaire-based surveys and focus groups were used to examine student perceptions and satisfaction. Surveys were analysed based on the frequency of responses to closed questions made on a 5-pont Likert scale, while a thematic analysis was performed on focus group transcripts. t-Tests were used to compare student awarded marks and examiner awarded marks and evaluate student performance.

RESULTS

Sixty-two physiotherapy students participated in the study. Mean response rate for questionnaires was 93% and eight students (13%) participated in the focus group. Participants found the video resources effective to support their learning (98% positive) and rating the video examples to be an effective learning activity (96% positive). Themes emergent from focus group responses were around improved understanding, reduced performance anxiety, and enjoyment. Students were, however, critical of the predictable nature of the example performances. Students in the current cohort supported by the video-based preparation activity exhibited greater practical examination marks than those from the previous year who were unsupported by the activity (mean 81.6 SD 8.7 vs. mean 78.1 SD 9.0, p=0.01).

CONCLUSION

A video-based learning activity was effective for preparing physiotherapy students for practical examinations and conferred benefits of reduced anxiety and improved performance.

Kinematic predictors of single-leg squat performance: a comparison of experienced physiotherapists and student physiotherapists

Background

The single-leg squat (SLS) is a common test used by clinicians for the musculoskeletal assessment of the lower limb. The aim of the current study was to reveal the kinematic parameters used by experienced and inexperienced clinicians to determine SLS performance and establish reliability of such assessment.

Methods

Twenty-two healthy, young adults (23.8 ± 3.1 years) performed three SLSs on each leg whilst being videoed. Three-dimensional data for the hip and knee was recorded using a 10-camera optical motion analysis system (Vicon, Oxford, UK). SLS performance was rated from video data using a 10-point ordinal scale by experienced musculoskeletal physiotherapists and student physiotherapists. All ratings were undertaken a second time at least two weeks after the first by the same raters. Stepwise multiple regression analysis was performed to determine kinematic predictors of SLS performance scores and inter- and intra-rater reliability were determined using a two-way mixed model to generate intra-class correlation coefficients (ICC_3,1) of consistency.

Results

One SLS per leg for each participant was used for analysis, providing 44 SLSs in total. Eight experienced physiotherapists and eight physiotherapy students agreed to rate each SLS. Variance in physiotherapist scores was predicted by peak knee flexion, knee medio-lateral displacement, and peak hip adduction (R² = 0.64, p = 0.01), while variance in student scores was predicted only by peak knee flexion, and knee medio-lateral displacement (R² = 0.57, p = 0.01). Inter-rater reliability was good for physiotherapists (ICC_3,1 = 0.71) and students (ICC_3,1 = 0.60), whilst intra-rater reliability was excellent for physiotherapists (ICC_3,1 = 0.81) and good for students (ICC_3,1 = 0.71).

Conclusion

Physiotherapists and students are both capable of reliable assessment of SLS performance. Physiotherapist assessments, however, bear stronger relationships to lower limb kinematics and are more sensitive to hip joint motion than student assessments.

Twice-weekly, in-school jumping improves lean mass, particularly in adolescent boys

OBJECTIVE

To determine the effect of a twice-weekly, school-based, 10-min jumping regime on muscle and fat tissue in healthy adolescent boys and girls.

METHODS

We replaced regular warm-up activities with jumping in physical education (PE) classes of early high school students for 8 months to observe the effect on muscle and fat tissue. A total of 99 adolescents (46 boys, 53 girls; 13.8 ± 0.4 years) volunteered to participate. Intervention group subjects performed 10 min of varied jumping activity, while control subjects performed a regular PE warm-up. Biometrics, Tanner staging, age of peak height velocity (PHV), vertical jump, whole body lean tissue and fat mass (dual-energy X-ray absorptiometry-derived) were measured at baseline and follow-up. Physical activity was determined by questionnaire.

RESULTS

There were no differences in any measured variable between control and intervention groups at baseline. Boys had a significantly older age of PHV than girls (p = 0.02). No group differences were detected for 8-month change in height, weight or maturity measures for the combined sample; however, at 8 months, jumpers had accrued greater lean tissue mass than controls (p = 0.002). Sex-specific analysis revealed that intervention group boys had gained more lean tissue mass than controls (p = 0.016) and experienced significant fat loss (p = 0.010) than controls, an effect that was not observed in the girls.

CONCLUSION

Regular, short-duration, jumping activity during adolescence increased lean tissue mass and boys additionally lost fat mass. Sex-specific and/or maturation-specific factors may explain the disparity in effect.

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

OBJECTIVES

To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass.

DESIGN

A repeated measure, prospective, observational, cohort study.

SETTING

Griffith University, Gold Coast, Australia.

PARTICIPANTS

37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season.

RESULTS

Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm(2); mid=1.296(0.093) g/cm(2); p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury.

CONCLUSIONS

Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.