Steven L Watson

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.

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.

Validity and test–retest reliability of a novel simple back extensor muscle strength test

Objectives: To develop and determine convergent validity and reliability of a simple and inexpensive clinical test to quantify back extensor muscle strength. Methods: Two testing sessions were conducted, 7 days apart. Each session involved three trials of standing maximal isometric back extensor muscle strength using both the novel test and isokinetic dynamometry. Lumbar spine bone mineral density was examined by dual-energy X-ray absorptiometry. Validation was examined with Pearson correlations (r). Test–retest reliability was examined with intraclass correlation coefficients and limits of agreement. Pearson correlations and intraclass correlation coefficients are presented with corresponding 95% confidence intervals. Linear regression was used to examine the ability of peak back extensor muscle strength to predict indices of lumbar spine bone mineral density and strength. Results: A total of 52 healthy adults (26 men, 26 women) aged 46.4 ± 20.4 years were recruited from the community. A strong positive relationship was observed between peak back extensor strength from hand-held and isokinetic dynamometry (r = 0.824, p < 0.001). For the novel back extensor strength test, short- and long-term reliability was excellent (intraclass correlation coefficient = 0.983 (95% confidence interval, 0.971–0.990), p < 0.001 and intraclass correlation coefficient = 0.901 (95% confidence interval, 0.833–0.943), p < 0.001, respectively). Limits of agreement for short-term repeated back extensor strength measures with the novel back extensor strength protocol were −6.63 to 7.70 kg, with a mean bias of +0.71 kg. Back extensor strength predicted 11% of variance in lumbar spine bone mineral density (p < 0.05) and 9% of lumbar spine index of bone structural strength (p < 0.05). Conclusion: Our novel hand-held dynamometer method to determine back extensor muscle strength is quick, relatively inexpensive, and reliable; demonstrates initial convergent validity in a healthy population; and is associated with bone mass at a clinically important site.

Lunging Exercise Potentiates a Transient Improvement in Neuromuscular Performance in Young Adults.

Abstract Horan, SA, Watson, SL, Lambert, C, and Weeks, BK. Lunging exercise potentiates a transient improvement in neuromuscular performance in young adults. J Strength Cond Res 29(9): 2532–2537, 2015—High-load resistance-based exercise is a common approach to facilitating improved neuromuscular performance via postactivation potentiation. Popular field-based warm-up activities, however, have been largely overlooked despite their specificity and practicality for sports performance. Therefore, the aim of this study was to investigate the effect of repeated bouts of alternating lunges on neuromuscular performance determined by a maximal vertical jump (VJ). Forty-three healthy young adults (24 women and 19 men: age, 25.6 ± 4.4 years) participated in the study. Maximal VJ performance was quantified by jump height (in centimeters), relative impulse (in N·s·kg−1), flight time (in seconds), and normalized peak vertical ground reaction force (GRFz, bodyweight [BW]) at baseline and after each of 6 sets of 20 alternate split lunges. A rating of perceived exertion (1–10 scale) was recorded from participants before each VJ. Jump height was greater than baseline for the first 4 trials (3.1–3.8%, p ⩽ 0.05), but no difference to baseline was observed on subsequent trials. Although there were no improvements for relative impulse over repeated trials, the sixth trial was significantly smaller than baseline (2.35 ± 0.38 vs. 2.26 ± 0.35 N·s·kg−1; p ⩽ 0.001). Similarly, no improvements were observed for flight time, although the first, fourth, fifth, and sixth trials were reduced compared with baseline performance (p ⩽ 0.01). No differences were observed for peak vertical GRFz (p > 0.05). In conclusion, a regimen of lunging exercise resulted in a transient improvement in maximal VJ performance. However, measures of flight time, impulse, and GRFz did not mirror the performance gain in jump height.

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.

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.

Response to Giangregorio et al.: “Intensity is a subjective construct”

Dear Editor, We thank the Too Fit to Fracture consensus panel members for their letter to the editor regarding our recent publication [1], and for the opportunity to highlight a central feature of the LIFTMOR trial. Giangregorio and colleagues suggest that we misinterpreted the Too Fit to Fracture exercise recommendations by citing their work to support our statement Bit is widely held that high-intensity exercises should not be attempted by individuals with established osteoporosis^. They contend that the Too Fit to Fracture exercise recommendations encourage individuals with osteoporosis to undertake progressive resistance training (PRT) at 8–10 repetitions which they describe as high-intensity [2]. (We note that the recommendation in the original Too Fit to Fracture publication we cited was actually 8–12 repetitions [ref. 3, Table 6, p 832]). We believe the issue is not a case of misinterpretation on our part [1], rather mis-definition of the term Bhigh-intensity^ on the part of the Too Fit to Fracture team [2, 3]. We agree that intensity has, on occasion, been a subjective construct with respect to resistance training. We argue however that, in recent years, a high level of accord has emerged in relation to definitive categories of resistance tra ining intensi ty. Those categories were summarised in a recent publication, edited by arguably the most highly respected experts in the field, as follows: BIntensities range from low (60 % and less of maximal capacity) to moderate (70 %–80 % of maximal capacity) to high (>85 % of maximal capacity)^ [4]. Those clearly delineated parameters of PRT intensity have been applied across a broad range of scientific and fitness industry standards over the past decade, to the extent that they could reasonably be considered to reflect current opinion. Some examples include the 2009 American College of Spo r t s Med i c i n e (ACSM) po s i t i o n s t a nd f o r BProgression Models in Resistance Training for Healthy Adults^ [5], the BResistance Training Intensity: Research and Rationale^ feature in ACSM Certified News [6], and the American Heart Association’s scientific statement on BResistance Exercise in Individuals With and Without Cardiovascular Disease^ [7]. A figure from the latter source (p579) clearly illustrates that high intensity resistance training involves loads that can be lifted fewer than 6 times, and that weights that can be lifted 8–15 times should be characterised as moderate intensity. In an effort to avoid subjectivity in our own description of the LIFTMOR resistance training programme, we adhered to those standardised criteria. In light of the availability of such definitive and recognised criteria for resistance training intensity, we were surprised by Giangregorio and colleagues’ statement that 8–10 repetitions (originally 8–12 repetitions) would Bby most standards...be considered relatively high-intensity resistance training^ [2]. In fact, Table 6 in the Too Fit to Fracture recommendations for vertebral osteoporosis (page 831) [3] specifically states that if a load cannot be lifted more than 8 times, it should be considered too hard for an individual with osteoporosis. Our interpretation of the Too Fit to Fracture position [3] was therefore that, by the standards of the currently accepted criteria, high intensity resistance training (<6 reps) was not recommended * B. R. Beck b.beck@griffith.edu.au

Bone and Muscle Health is Associated with Physical Activity and Neuromuscular Performance in Older Men: 1724 Board #10 May 29, 2

Physical activity exerts a powerful influence on our musculoskeletal health as we age. In fact, some conditions such as osteoporosis and sarcopenia, which are strongly age-related, may be prevented with adequate physical activity participation. PURPOSE: Our aim was to quantify recent and lifetime physical activity participation to determine their relationship with musculoskeletal health and neuromuscular performance in older men. METHODS: Thirty-six healthy older men (69.5 ± 5.8 yrs) volunteered to participate. Past and current physical activity participation was estimated with the Bone-specific Physical Activity Questionnaire (BPAQ) and International Physical Activity Questionnaire, respectively. Neuromuscular performance was determined by calculating impulse from ground reaction forces during a maximal vertical jump. Lean mass, fat mass and regional bone mineral density (BMD) measures were obtained using dual-energy x-ray absorptiometry. Osteoporosis was classified according to BMD T-scores, while sarcopenia was identified by relative appendicular lean mass. RESULTS: Participants in the upper tertile for relative impulse exhibited less fat than those in the bottom tertile (29.9 ± 8.3 vs. 20.6 ± 9.3 kg, p = 0.04). Based on absolute impulse, the bottom tertile exhibited lower appendicular lean mass than the middle (26.0 ± 2.0 vs. 29.3 ± 1.5 kg, p = 0.001) and upper tertiles (26.0 ± 2.0 vs. 29.6 ± 2.9 kg, p = 0.001). Participants who engaged in vigorous physical activity produced larger impulse than those not engaged in vigorous activity (193.5 ± 19.1 vs. 172.2 ± 24.7 Ns, p = 0.04). Osteoporotic participants (n = 10) had lower childhood BPAQ scores than non-osteoporotic participants (16.1 ± 19.1 vs. 35.5 ± 24.4, p = 0.03). Sarcopenic participants (n = 7) produced lower impulse during the maximal vertical jump than non-sarcopenic participants (183.2 ± 21.3 vs. 156.7 ± 33.1 Ns, p = 0.01). CONCLUSIONS: Superior neuromuscular performance was associated with low fat mass, high lean mass and participation in vigorous physical activity. Further, childhood bonerelevant physical activity could differentiate men with and without osteoporosis. Our results highlight the importance of physical activity during development and aging for lifelong musculoskeletal health and function.