Trunk muscle activity is modified in osteoporotic vertebral fracture and thoracic kyphosis with potential consequences for vertebral health

Evaluation of trunk muscle coactivation predictions in multi-body models

Musculoskeletal simulations with muscle optimization aim to minimize muscle effort, hence are considered unable to predict the activation of antagonistic muscles. However, activation of antagonistic muscles might be necessary to satisfy the dynamic equilibrium. This study aims to elucidate under which conditions coactivation can be predicted, to evaluate factors modulating it, and to compare the antagonistic activations predicted by the lumbar spine model with literature data. Simple 2D and 3D models, comprising of 2 or 3 rigid bodies, with simple or multi-joint muscles, were created to study conditions under which muscle coactivity is predicted. An existing musculoskeletal model of the lumbar spine developed in AnyBody was used to investigate the effects of modeling intra-abdominal pressure (IAP), linear/cubic and load/activity-based muscle recruitment criterion on predicted coactivation during forward flexion and lateral bending. The predicted antagonist activations were compared to reported EMG data. Muscle coactivity was predicted with simplified models when multi-joint muscles were present or the model was three-dimensional. During forward flexion and lateral bending, the coactivation ratio predicted by the model showed good agreement with experimental values. Predicted coactivation was negligibly influenced by IAP but substantially reduced with a force-based recruitment criterion. The conditions needed in multi-body models to predict coactivity are: three-dimensionality or multi-joint muscles, unless perfect antagonists. The antagonist activations are required to balance 3D moments but do not reflect other physiological phenomena, which might explain the discrepancies between model predictions and experimental data. Nevertheless, the findings confirm the ability of the multi-body trunk models to predict muscle coactivity and suggest their overall validity.

The 7th cervical vertebra wall distance (C7WD) identifies balance control, functional mobility and the risk of multiple falls in elderly community-dwelling women with thoracic hyperkyphosis

BACKGROUND

Thoracic hyperkyphosis is common in the elderly, especially in women, and results in impaired balance control, impaired functional mobility and an increased risk of multiple falls. The 7th cervical vertebra wall distance (C7WD) is a practical method for evaluating thoracic hyperkyphosis.

OBJECTIVE

This study calculated C7WD cut-off scores that may identify impaired balance control, impaired functional mobility and an increased risk of multiple falls in elderly community-dwelling women with thoracic hyperkyphosis. This study also explored the correlation between C7WD, balance control and functional mobility.

METHODS

Sixty participants were assessed for thoracic hyperkyphosis using the C7WD, balance control using the functional reach test (FRT), functional mobility using the timed up-and-go test (TUG) and a history of falls using their personal information.

RESULTS

The data indicated that a C7WD of at least 7.95 cm, 8.1 cm and 8.8 cm had a good to excellent capability of identifying impaired balance control, impaired functional mobility and an increased risk of multiple falls, respectively. The C7WD results were significant and correlated with balance control (rs=-0.68) and functional mobility (rs= 0.41).

CONCLUSIONS

The C7WD may be utilised as a screening tool for these three impairments in this population.

Exploring the Association between Pain and Fracture Characteristics in Women with Osteoporotic Vertebral Fractures

Purpose: The purpose of this study was to estimate the association between pain and the number, severity, and location of fractures in women with osteoporotic vertebral fractures. Method:We used an 11-point numeric pain rating scale to assess pain during movement in the preceding week and lateral spinal radiographs to confirm number, location, and severity of vertebral fractures. In model 1, we assessed the association between pain during movement and the number, severity, and location of fractures. We adjusted model 2 for pain medication use and age. Results: The mean age of participants was 76.4 (SD 6.9) years. We found no statistically significant associations between pain and fracture number (estimated β = 0.23, 95% CI: ‒0.27, 0.68), fracture severity (estimated β = ‒0.46, 95% CI: ‒1.38, 0.49), or fracture location at T4–T8 (estimated β = 0.06, 95% CI: ‒1.26, 1.34), T9–L1 (estimated β = 0.35, 95% CI: ‒1.17, 1.74), or L2–L4 (estimated β = 0.40, 95% CI: ‒1.01, 1.75). Age and pain medication use were not significantly associated with pain. Model 1 accounted for 4.7% and model 2 for 7.2% of the variance in self-reported pain. Conclusion: The number, location, and severity of fractures do not appear to be the primary explanation for pain in women with vertebral fractures. Clinicians must consider other factors contributing to pain.

Comparison of the postoperative changes in trunk and lower extremity muscle activities between patients with adult spinal deformity and age-matched controls using surface electromyography

STUDY DESIGN

A prospective study.

OBJECTIVE

To investigate the paravertebral and lower extremity muscle activities using surface electromyography (S-EMG) in patients with adult spinal deformity (ASD) comparing with those of age-matched controls. Although the paravertebral muscle is greatly involved in ASD pathology, little is known about the contribution of lower extremity muscle on maintaining standing posture.

METHODS

Fourteen patients with ASD (1 man, 13 women; mean age, 67.1 years) who underwent corrective fusion surgery with at least 2 years of follow-up and age-matched controls (1 men, 7 women; mean age, 69.3 years) were enrolled. The muscle activities of the thoracic and lumbar erector spinae (TES and LES), external oblique (EO), gluteus maximus (GM), rectus femoris (RF), and biceps femoris (BF) were recorded in the upright and anterior flexion positions using S-EMG pre-operatively and 1 year post-operatively.

RESULTS

Compared with controls, patients showed a significantly higher muscle activity in the LES and BF at rest in a standing position. After corrective fusion surgery, the muscle activity of LES decreased and that of RF increased (p < 0.05), and the changes reached the level of the controls. When the posture changed from upright to anterior flexion, the controls showed increased muscle activity of the BF, whereas the patients showed decreased muscle activity of the TES and RF and increased muscle activity of the BF. Post-operatively, muscle activity of the TES, LES, GM, and BF increased and that of the RF decreased.

CONCLUSIONS

ASD patients required a higher activity of the lower extremity and trunk muscles to maintain a standing position compared to the age-matched controls. Significant increase of the GM, BF, and TES muscle activities during anterior bending suggest the presence of mechanical stress concentration caused by fixed lumbar spine.

LEVEL OF EVIDENCE

Level III.

Long-Term Efficacy of Treatment Effects After a Kyphosis Exercise and Posture Training Intervention in Older Community-Dwelling Adults: A Cohort Study

BACKGROUND AND PURPOSE

Treatments that prevent worsening kyphosis are important due to the progressive nature of kyphosis with aging. We assessed long-term efficacy of treatment effects after a short-term kyphosis exercise and posture training intervention in a cohort study among older adults with hyperkyphosis, and investigated whether long-term treatment effects differ among males and females.

METHODS

In the original kyphosis intervention, 112 older adults enrolled in a waitlist design randomized controlled trial. One hundred three participants, mean age 70.0 (5.7) years and kyphosis 52.0° (7.4°), completed a twice weekly, 3-month, group exercise and posture training intervention, and were eligible to enroll in the follow-up study. We compared (1) change in outcomes pre-/postintervention to change postintervention over the follow-up period, (2) change in outcomes pre-/postintervention and postintervention to follow-up, stratified by sex, and (3) long-term change postintervention to follow-up in males and females. Primary outcome was change in kyphometer-measured thoracic kyphosis. Secondary outcomes were change in lumbar lordosis, objective measures of physical function, self-reported measures of physical activity, and health-related quality of life (HRQoL).

RESULTS AND DISCUSSION

Forty-three participants, 42% of the eligible cohort, returned for follow-up, a mean 3.0 (0.7) years after completing the original intervention. Participants (27 females and 16 males) were 73.8 (6.1) years old, with mean kyphosis 48.9° (11.9°) at follow-up. Kyphosis declined -1.5° (95% confidence interval [CI]: -3.9° to 1.0°) postintervention to follow-up and this was no different than change pre-/postintervention, P = .173. Lordosis improved 8.9° (95% CI: 6.2° to 11.6°), more than change pre-/postintervention, P < .001. Gait speed measure of physical function increased 0.08 (95% CI: 0.02 to 0.14) m/s, Physical Activity Scale for the Elderly (PASE) measure of physical activity increased 4 (95% CI: -16 to 24) points, and Patient-Reported Outcomes Measurement Information System (PROMIS) mental health T-score measure of HRQoL increased 1.1 (95% CI: -1.0 to 3.1) points, but these improvements were not significantly more than change pre-/postintervention, P > .050. Other measures of physical function (modified Physical Performance Test [PPT], Timed Up and Go, and 6-minute walk) and HRQoL (Scoliosis Research Society [SRS-30] self-image and PROMIS physical function and physical health) declined at follow-up, significantly more than change pre/postintervention, P ≤ .050. Comparing change in outcomes pre-/postintervention and postintervention to follow-up, stratified by sex, both males and females increased lordosis, and decreased modified PPT and 6-minute walk measures of physical function, P < .050. Males and females differed in long-term change postintervention to follow-up. Time loaded standing and PASE improved in females compared with males, P = .008 and P = .092, respectively, and PROMIS mental health, physical health, and physical function declined in females compared with males, P = .073, P = .025, and P = .005, respectively.

CONCLUSIONS

In our follow-up study, a mean of 3.0 (0.07) years after a 3-month kyphosis exercise and posture training intervention, kyphosis maintained and did not progress as expected with age. There was long-term improvement in lordosis. Compared with treatment effects from the short-term intervention, gait speed maintained equally well in males and females, while trunk endurance improved in females. Further investigation of long-term benefits of a short-term kyphosis exercise and posture training intervention is warranted.

The association between trunk muscle endurance, balance and falls self-efficacy in women with osteoporotic vertebral fractures: an exploratory analysis from a pilot randomized controlled trial

BACKGROUND

Trunk muscle endurance may be associated with balance and falls self-efficacy for people with osteoporosis. However, all previous studies have examined trunk muscle strength rather than endurance.

PURPOSE

To explore the relationships between trunk muscle endurance and standing balance and falls self-efficacy for women with vertebral fractures.

MATERIALS AND METHODS

This is an exploratory, secondary analysis of baseline data of a pilot randomized controlled trial in Ontario, Canada. Thirty-one women with osteoporosis, aged 65 years or older, with at least one vertebral fracture were included. The associations between balance (Balance Outcome Measure for Elder Rehabilitation) and trunk muscle endurance (Timed Loaded Standing Test) and falls self-efficacy (Falls Efficacy Scale International) and trunk muscle endurance were tested via Spearman rank order correlation with Fisher's z transformations.

RESULTS

Trunk muscle endurance was correlated with better balance performance on the Balance Outcome Measure for Elder Rehabilitation [Spearman correlation coefficient, 0.71; 95% confidence interval: 0.47-0.85; p < 0.001], but not with falls self efficacy (Spearman correlation coefficient; -0.22; 95% confidence interval: -0.53 to 0.14; p = 0.23).

CONCLUSIONS

Trunk muscle endurance was moderately associated with better standing balance performance but not falls self-efficacy, highlighting the importance of trunk muscle endurance for standing balance for older adults with osteoporosis and vertebral fractures.Implications for RehabilitationOlder adults with osteoporosis and vertebral fractures who have better trunk muscle endurance may also have better standing balance.There was no association between trunk muscle endurance and how confident a person is that they will not fall while completing various activities of daily living.Trunk muscle endurance training could be included as part of a standing balance rehabilitation program for this population.

Muscle activity during backward perturbation response in patients with clinical vertebral compression fractures

The present study examined muscle activity in response to backward perturbation in patients with clinical vertebral compression fracture (CVCF). The subjects were 32 patients aged 65 years and above consisting of 16 each with (CVCF group) and without (control group) CVCF. The time to peak activity, and time of onset of muscle activity of the anterior tibial, vastus medialis, and rectus abdominis muscles when unexpected backward perturbation was applied were evaluated by surface electromyography. The strength of perturbation was 4% or 6% of the subject's body weight. In addition, the presence of the stepping reaction to perturbation, severity of low back pain, and vertebral alignment were evaluated. Each item was compared between the two groups. In the CVCF group, kyphosis and severity of low back pain were significantly more severe, the time to peak activity of the anterior tibial muscle after the application of perturbation at 6% of the body weight was significantly shorter, and the time of onset of activity of the rectus abdominis muscle was significantly delayed. This suggests that the time to peak activity of the anterior tibial muscle is shortened and the time of onset of activity of the rectus abdominis muscle is delayed in unexpected backward perturbation in patients with CVCF.

Back Muscle Function in Older Women With Age-Related Hyperkyphosis: A Comparative Study

OBJECTIVE

The purpose of this study was to compare static maximal back extensor muscle force, endurance, and characteristics of flexion relaxation phenomenon (FRP) in older women with and without age-related hyperkyphosis.

METHODS

Maximum back extensor force and endurance measured in a sitting position with a designed load cell setup; appearance, onset, and offset angles of FRP; and extension relaxation ratio (ERR) during a dynamic flexion-extension task were compared between 24 older women with hyperkyphosis (thoracic kyphosis angle ≥50°), mean age 65 ± 4.4 years, and 24 older women without hyperkyphosis (thoracic kyphosis angle ≪50°), mean age 63 ± 4.3 years. Variables of force, endurance, angles of FRP, and ERR were analyzed using an independent sample t test. A χ² test was used to identify differences between groups in FRP appearance.

RESULTS

Static back extensor force and endurance were significantly lower among those with versus those without hyperkyphosis (P ≪ .001). Although the 2 groups did not differ in FRP appearance and ERR in the superficial erector spinal muscles (P ≫ .05), FRP in the hyperkyphosis group started sooner and ended later than in the group without hyperkyphosis (P ≪ .05).

CONCLUSION

Our study indicates that women with age-related hyperkyphosis had decreased static maximal force and endurance of the back extensor muscles and prolonged myoelectrical silence of the superficial erector spinal muscles. Reduced endurance of the superficial erector spinal muscles may trigger early onset of FRP and prolonged relaxation of these muscles.

Analysis of kyphosis, vertebral fracture and bone mineral density measurement in women living in nursing homes

OBJECTIVES

To analyze the relationship between vertebral fracture, degree of kyphosis, and BMD in women living in nursing homes.

METHODS

This cross-sectional study was carried out in the Department of Physical Medicine and Rehabilitation, Hitit University Hospital, Corum, Turkey, betweenJanuary 2014 and January 2015. Of the 126 female patients who participated in the study, 48 lived in nursing homes (nursing-home-group [NHG]), 78 lived in non-nursing home settings (control-group [CG]). Vertebral fractures were evaluated via the semi-quantitative Genant method. Cases in which a Cobb angle measured 40 degrees or more resulted in a diagnosis of kyphosis.

RESULTS

The mean age of participants in the NHG was 77.2±7.6 years and 76.8±6.2 years in the CG (p greater than 0.05). The kyphosis rate in the NHG was found to be higher at 52.1% compared to 27.7% for the CG (p less than 0.001). In the NHG, 68.7% had osteoporosis, 31.3% had osteopenia; in the CG, 55.2% had osteoporosis, 32% had osteopenia, 12.8% had normal values (p less than 0.05).The vertebral fracture rate was 37.5% in the NHG and 24.3% in the CG (p greater than 0.05). The Cobb angle had correlation with the number of fractures in both groups (p less than 0.05).

CONCLUSIONS

The osteoporosis and kyphosis rates of women living in NHG were higher than those of women living in CG. As kyphosis and the number of fractures are correlated, it is important to analyze kyphosis in women residing in NHG.

Center of Pressure Trace and Sensory Components of the Limits of Stability Test in Older Adults With Vertebral Compression Fractures

BACKGROUND AND PURPOSE

Patients with vertebral compression fracture (VCF) usually exhibit impaired postural control and consequently are at an increased risk of falling. This study aimed to assess the sensory and kinematic components of the limits of stability (LOS) test in patients with VCF.

METHODS

This study enrolled 13 adults with VCF (VCF group), 13 older adults without spinal deformity (NE group), and 13 young adults (NY group). The Biodex balance system was employed to calculate the balance score and the LOS of participants. An inertia motion system was used to record kinematic data. The center of pressure signals of postural stability and LOS were used to calculate the frequency power spectrum for interpreting the sensory component.

RESULTS

Compared with the NY group, the VCF group exhibited a longer reaction time and lower balance scores and used a higher median frequency in the medial-lateral and anterior-posterior direction of body acceleration to perform the LOS test. The required ranges of hip rotation and pelvic pitch were significantly higher in the older adult group than in the NY group. In the postural stability test, the VCF group exhibited significantly higher frequency power in the 0.01- to 0.5-Hz band (visual and vestibular) under both the eyes-closed and eyes-open conditions than the other groups. In the LOS test, the VCF group also exhibited lower sensory component activity than the other groups, particularly in vestibular function (0.1-0.5 Hz).

CONCLUSIONS

Both musculoskeletal degeneration and sensory integration impairment may contribute to poor direction control and a longer reaction time in patients with VCF.

Which strength and balance activities are safe and efficacious for individuals with specific challenges (osteoporosis, vertebral fractures, frailty, dementia)?: A Narrative review

Physical activity guidelines advocate the inclusion of strength and balance activities, twice a week, for adults and older adults, but with caveat that in some individuals there will be certain movements and activities that could lead to adverse events. This scoping review summarizes the evidence about how safe and efficacious these activities are in older adults with specific challenges that might make them more prone to injury (e.g. having recently fractured or at risk of fracture (osteoporosis) or those who are frail or who have cognitive impairment). The review identified that for prevention of falls in people with a falls history and/or frailer older adults, structured exercise programmes that incorporate progressive resistance training (PRT) with increasing balance challenges over time are safe and effective if performed regularly, with supervision and support, over at least 6 months. Some minor adverse effects mainly transient musculoskeletal pain) have been reported. For those with a higher risk of falls and fractures (very poor balance, vertebral fractures), supervised structured exercise programmes are most appropriate. People with diagnosed osteoporosis should be as active as possible and only avoid activities with a high risk of falls if they are naïve to those activities. For those in transition to frailty who have poor strength and balance, exercises that are known to help maintain strength and balance (such as Tai Chi) are effective in preventing a decline in falls risk. For the very frail older adult, supervised structured exercise that has PRT, balance training and some endurance work, supervised and progressed by a trained person are advocated.

Comparative study of the paraspinal muscles after OVF between the insufficient union and sufficient union using MRI

Background

Identification of poor prognostic factors for OVF is important but has not yet been clearly established. Despite paraspinal muscles could play an important role in the etiology of OVF, what influence time-dependent changes in paraspinal muscles have after OVF, and the impact on conservative treatments for patients who have an OVF remain largely unknown. The purposes of this study were to (1) evaluate time-dependent changes of the paraspinal musculature using MRI after injury in patients with osteoporotic vertebral fractures (OVFs), and (2) compare paraspinal muscles between conservatively treated patients with OVF who have successful union and those failed to conservative treatment.

Methods

A total of 115 consecutive patients who had sustained a recent OVF injury in the thoracolumbar region were assessed for eligibility using medical records and all required data were available from 90 patients who had been followed up for at least 6 months. Patients who needed to undergo surgery and patients who were diagnosed as having insufficient union after 6 months of follow-up were assigned to a group with insufficient union. Lumbar trunk parameters, relative cross-sectional area (rCSA) and proportion of fat infiltration (FI%) were calculated from MRI. To evaluate the time-dependent changes in the paraspinal muscle in patients after OVF injury, correlations between the timing of MRI and rCSA, FI% were determined. To clarify the impact of paraspinal muscles on the outcome of conservative treatments of patients with OVF, we compared rCSA between the groups.

Results

Sixty-five patients were assigned to a group with insufficient union and 25 patients were assigned to a group with successful union. FI% of the multifidus and erector spinae in the group with insufficient union were significantly greater than in the group with union. The timing of MRI in relation to initial injury was significantly correlated with FI% of the multifidus and erector spinae. rCSA of the erector spinae was significantly larger in the group with successful union than in the group with insufficient union.

Conclusions

These findings indicated a time-dependent increase of fatty degeneration of the multifidus and erector muscles, but no change in the rCSA and larger rCSAs of spinal erectors may play a role in successful union in patients with OVF.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2064-0) contains supplementary material, which is available to authorized users.

Is the timed loaded standing test a valid measure of back muscle endurance in people with vertebral osteoporosis?

Timed loaded standing (TLS) is a suggested measure of back muscle endurance for people with vertebral osteoporosis. Surface electromyography revealed back muscles work harder and fatigue during TLS. The test end-point and total time were associated with back fatigue. The findings help demonstrate the concurrent validity of the TLS test.

INTRODUCTION

The TLS test is suggested as a measure of back muscle endurance for patients with vertebral osteoporosis. However, to date, no study has demonstrated that TLS does measure back extensor or erector spinae (ES) muscle endurance. We used surface electromyography (sEMG) to investigate the performance of the thoracic ES muscles during TLS.

METHODS

Thirty-six people with vertebral osteoporosis with a mean age of 71.6 (range 45-86) years participated. sEMG recordings were made of the ES at T3 and T12 bilaterally during quiet standing (QS) and TLS. The relative (%) change in sEMG amplitude between conditions was compared. Fatigue was evaluated by analysing the change in median frequency (MF) of the sEMG signal during TLS, and the correlation between maximal TLS time and rate of MF decline was examined.

RESULTS

Activity in the ES increased significantly during TLS at all electrode locations. During TLS, the MF declined at a mean rate of -24.2% per minute (95% C.I. -26.5 to -21.9%). The MF slope and test time were strongly correlated (r² = 0.71), and at test end, the final MF dropped to an average 89% (95% C.I. 85 to 93%) of initial MF. Twenty-eight participants (78%) reported fatigue was the main reason for stopping, and for eight (22%), it was pain.

CONCLUSIONS

This study demonstrates that TLS challenges the ES muscles in the thoracic region and results in ES fatigue. Endurance time and the point at which the TLS test ends are strongly related to ES fatigue.

Targeted spine strengthening exercise and posture training program to reduce hyperkyphosis in older adults: results from the study of hyperkyphosis, exercise, and function (SHEAF) randomized controlled trial

A 6-month randomized controlled trial of spine-strengthening exercise and posture training reduced both radiographic and clinical measures of kyphosis. Participants receiving the intervention improved self-image and satisfaction with their appearance. Results suggest that spine-strengthening exercise and postural training may be an effective treatment option for older adults with hyperkyphosis.

INTRODUCTION

The purpose of the present study is to determine in a randomized controlled trial whether spine-strengthening exercises improve Cobb angle of kyphosis in community-dwelling older adults.

METHODS

We recruited adults ≥60 years with kyphosis ≥40° and enrolled 99 participants (71 women, 28 men), mean age 70.6 ± 0.6 years, range 60-88, with baseline Cobb angle 57.4 ± 12.5°. The intervention included group spine-strengthening exercise and postural training, delivered by a physical therapist, 1-h, three times weekly for 6 months. Controls received four group health education meetings. The primary outcome was change in the gold standard Cobb angle of kyphosis measured from standing lateral spine radiographs. Secondary outcomes included change in kyphometer-measured kyphosis, physical function (modified Physical Performance Test, gait speed, Timed Up and Go, Timed Loaded Standing, 6-Min Walk), and health-related quality of life (HRQoL) (PROMIS global health and physical function indexes, SRS-30 self-image domain). ANCOVA was used to assess treatment effects on change from baseline to 6 months in all outcomes.

RESULTS

There was a -3.0° (95% CI -5.2, -0.8) between-group difference in change in Cobb angle, p = 0.009, favoring the intervention and approximating the magnitude of change from an incident vertebral fracture. Kyphometer-measured kyphosis (p = 0.03) and SRS-30 self-esteem (p < 0.001) showed favorable between-group differences in change, with no group differences in physical function or additional HRQoL outcomes, p > 0.05.

CONCLUSIONS

Spine-strengthening exercise and posture training over 6 months reduced kyphosis compared to control. Our randomized controlled trial results suggest that a targeted kyphosis-specific exercise program may be an effective treatment option for older adults with hyperkyphosis.

TRIAL REGISTRATION NUMBER AND NAME OF TRIAL REGISTER

ClinicalTrials.gov; identifier NCT01751685.

Age-related hyperkyphosis: update of its potential causes and clinical impacts-narrative review

The present study aims to qualitatively review the contributing factors and health implications of age-related hyperkyphosis. We conducted a narrative review of observational and cohort studies describing the risk factors and epidemiology of hyperkyphosis from 1955 to 2016 using the following key words: kyphosis, hyperkyphosis, posture, age-related hyperkyphosis, kyphotic posture, aetiology and causes. This review included 77 studies. Approximately 60-70 % of the most severe hyperkyphosis cases have no evidence of underlying vertebral compression fractures. Other proposed factors contributing to hyperkyphosis are degenerative disc disease, weakness of back extensor muscles and genetic predisposition. Strength and endurance of back extensor muscles are very important for maintaining normal postural alignment. Recent evidence suggests that age-related hyperkyphosis is not equivalent to spinal osteoporosis. Due to the negative impact of hyperkyphosis on physical function, quality of life and mortality rates, physicians should focus not only on osteoporosis, but also on age-related postural changes. More research about the relationship between spinal morphology and modifiable factors, especially the structural and functional parameters of trunk muscles, could further illuminate our understanding and treatment options for hyperkyphosis.

Exercise, muscle, and the applied load-bone strength balance

A fracture occurs when the applied load is greater than the bone can withstand. Clinical practice guidelines for the management of osteoporosis include recommendations for exercise; one of the few therapies where the proposed anti-fracture mechanisms that include effects on both bone strength and applied loads, where applied loads can come in the form of a fall, externally applied loads, body weight, or muscle forces. The aim of this review is to provide an overview of the clinical evidence pertaining to the potential efficacy of exercise for preventing fractures in older adults, including its direct effects on outcomes along the causal pathway to fractures (e.g., falls, posture, bone strength) and the indirect effects on muscle or the muscle-bone relationship. The evidence is examined as it pertains to application in clinical practice. Considerations for future research are discussed, such as the need for trials in individuals with low bone mass or students that evaluate whether changes in muscle mediate changes in bone. Future trials should also consider adequacy of calorie or protein intake, the confounding effect of exercise-induced weight loss, or the most appropriate therapeutic goal (e.g., strength, weight bearing, or hypertrophy) and outcome measures (e.g., fracture, disability, cost-effectiveness).

Exercise and Sports Science Australia (ESSA) position statement on exercise prescription for the prevention and management of osteoporosis

OBJECTIVES

Osteoporotic fractures are associated with substantial morbidity and mortality. Although exercise has long been recommended for the prevention and management of osteoporosis, existing guidelines are often non-specific and do not account for individual differences in bone health, fracture risk and functional capacity. The aim of the current position statement is to provide health practitioners with specific, evidence-based guidelines for safe and effective exercise prescription for the prevention or management of osteoporosis, accommodating a range of potential comorbidities.

DESIGN

Position statement.

METHODS

Interpretation and application of research reports describing the effects of exercise interventions for the prevention and management of low bone mass, osteoporosis and osteoporotic fracture.

RESULTS

Evidence from animal and human trials indicates that bone responds positively to impact activities and high intensity progressive resistance training. Furthermore, the optimisation of muscle strength, balance and mobility minimises the risk of falls (and thereby fracture), which is particularly relevant for individuals with limited functional capacity and/or a very high risk of osteoporotic fracture. It is important that all exercise programs be accompanied by sufficient calcium and vitamin D, and address issues of comorbidity and safety. For example, loaded spine flexion is not recommended, and impact activities may require modification in the presence of osteoarthritis or frailty.

CONCLUSIONS

Specific guidelines for safe and effective exercise for bone health are presented. Individual exercise prescription must take into account existing bone health status, co-morbidities, and functional or clinical risk factors for falls and fracture.

The Role of Trunk Musculature in Osteoporotic Vertebral Fractures: Implications for Prediction, Prevention, and Management

This review examines the current evidence for associations between vertebral fractures (VFx), the most common type of fracture in older adults, and trunk muscles, which are intimately tied to spinal loading and function. Individuals with prevalent VFxs have more fat infiltration in the trunk muscles, lower trunk extension strength, and altered muscle activation patterns. However, no longitudinal studies have examined whether assessment of trunk muscle can contribute to prediction of fracture risk. A few studies report that exercise interventions targeting the trunk muscles can reduce the risk of VFx, improve trunk strength and endurance in patients who have had a VFx, and reduce the risk of falling, a common cause of VFx, but the quality of evidence is low. Trunk muscles likely have an important role to play in prediction, prevention, and management of VFx, but additional longitudinal studies and randomized controlled trials are needed to clarify this role.

High risk of fall, poor physical function, and low grip strength in men with fracture-the STRAMBO study

BACKGROUND

Several studies assessed the association of prevalent fractures with muscle mass, strength, and physical capacity in men. Clinical impact of these associations is not clear, and they could be influenced by confounders. Our aim was to assess the association of the prevalent fractures with muscle strength, physical function, and the risk of subsequent falls in older men after adjustment for muscle mass and potential confounders.

METHODS

In a cohort of 890 men aged 50 and older, we assessed appendicular skeletal muscle mass (ASM) by DXA, grip strength, physical function (chair stands, static, and dynamic balance). Relative ASM (RASM) was calculated as ASM / (height)(2). Then, 813 men aged 60 and over were followed up prospectively for 5 years and 144 sustained >1 incident falls. All the analyses were adjusted for lifestyle factors, co-morbidities, and hormones known to influence muscle and physical function.

RESULTS

Low leisure physical activity, very high occupational physical activity, Parkinson's disease, diabetes mellitus, low apparent free testosterone concentration (AFTC), as well as Grade 2 and 3 vertebral fractures and multiple fractures were associated with lower grip strength when adjusted for confounders including upper limb RASM. Low leisure physical activity, very high occupational physical activity, diabetes mellitus, prior stroke, low AFTC and 25-hydroxycholecalciferol, high C-reactive protein, vertebral fractures, and non-vertebral fractures were associated with poor physical function (lowest quintile of the score of tests) when adjusted for confounders including lower limb RASM. Grade 2 and 3 and multiple vertebral fractures were associated with twofold higher risk of multiple falls after adjustment for confounders. Men having multiple fractures had a twofold higher risk of multiple falls after adjusting for confounders. In multivariable models, risk of falls increased proportionally to the increasing severity and number of vertebral fractures as well as to the increasing number of all fractures.

CONCLUSIONS

In older men, Grade 2 and 3 vertebral fractures and multiple vertebral and non-vertebral fractures are associated with lower grip strength, poor physical function, and higher risk of multiple falls after adjustment for multiple confounders. This suggests a real direct association. One fracture can initiate a vicious circle leading to another fracture; thus, patients with fractures need physical therapy regardless of their general health status.

Mechanism of camptocormia in Parkinson's disease analyzed by tilt table-EMG recording

BACKGROUND

We previously classified camptocormia of Parkinson's disease (PD) into upper and lower types based on the inflection point, and reported improvement of upper camptocormia after lidocaine injection into the external oblique. However, the exact pathophysiology of this phenomenon remains obscure.

METHODS

Surface electromyography (sEMG) was recorded in 11 PD patients with upper camptocormia, 11 PD patients with lower camptocormia, and 10 age-matched PD patients without postural deformity. Electrodes were positioned above the external oblique, hip flexors and paraspinal muscles at Th11 level bilaterally. Recording commenced with the patient in supine position on a tilt table, and continued when the table was tilted up to vertical position. Lidocaine was injected into the external oblique in patients with upper camptocormia and the psoas major in patients with lower camptocormia.

RESULTS

All patients with upper and lower camptocormia developed the corresponding camptocormic posture during tilt up. The onset of camptocormic posture was preceded by the appearance of sEMG activity in the external oblique in 10 out of 11 patients with upper camptocormia, but less frequently in patients with lower camptocormia and the controls. Hip flexors sEMG activity was recorded in almost all patients. Posture was improved in 8 out of 9 patients with upper camptocormia, and 9 out of 11 patients with lower camptocormia following injections of lidocaine.

CONCLUSIONS

The results suggest the external oblique is involved, at least in part, in the development of upper camptocormia. Although EMG findings cannot differentiate pathogenicity, the psoas major is probably involved in lower camptocormia.