Back Extensor Strength Research Articles

Exploring Associations of Preoperative Physical Performance With Postoperative Outcomes After Lumbar Spinal Fusion: A Machine Learning Approach

ObjectiveTo explore the association between preoperative physical performance with short- and long-term postoperative outcomes in patients undergoing lumbar spinal fusion (LSF). DesignRetrospective cohort. SettingUniversity hospital. ParticipantsSeventy-seven patients (N=77) undergoing elective LSF were preoperatively screened on patient demographics, patient-reported outcome measures, and physical performance measures (movement control, back muscle endurance strength and extensor strength, aerobic capacity, flexibility). InterventionsNot applicable. Main Outcome MeasuresAssociations between preoperative variables and inpatient functional recovery, hospital length of stay (LOS), and 1- to 2-year postoperative pain reduction were explored using random forest analyses assessing the relative influence of the variable on the outcome. ResultsAerobic capacity was associated with fast functional recovery <4 days and prolonged functional recovery >5 days (median z scores=7.1 and 12.0). Flexibility (median z score=4.3) and back muscle endurance strength (median z score=7.8) were associated with fast functional recovery <4 days. Maximum back extensor strength was associated with prolonged functional recovery >5 days (median z score=8.6). Flexibility (median z score=5.1) and back muscle endurance strength (median z score=13.5) were associated with short LOS <5 days. Aerobic capacity (median z score=8.7) was associated with prolonged LOS >7 days. Maximum back extensor strength (median z score=3.8) was associated with 1- to 2-year postoperative pain reduction and aerobic capacity (median z score=2.8) was tentative. ConclusionsPhysical performance measures were associated with both short- and long-term outcomes after LSF. Adding these measures to prediction models predicting outcomes after LSF may increase their accuracy.

Impact of appendicular and trunk skeletal muscle mass and back extensor strength on sagittal spinal alignment in Japanese women without vertebral fracture

ObjectivesProgressive and generalized loss of skeletal muscle mass (SMM) and strength are characteristics of sarcopenia. However, the impact of appendicular and trunk SMM and back extensor strength (BES) on spinal sagittal alignment remains unclear. Herein, we investigate the relationship between these factors and spinal sagittal alignment. MethodsIn total, 202 women without vertebral fractures (median age, 66.9 years; interquartile range, 61.4–71.9 years) were analyzed at an orthopedic outpatient clinic. Pelvic incidence (PI), lumbar lordosis (LL), sagittal vertical axis (SVA), and pelvic tilt (PT) were measured on whole spine radiographs. Body mass index (BMI), appendicular and trunk relative SMM index, and BES were also evaluated. These measurements were compared between spinal sagittal alignment groups using the Mann–Whitney U test. Finally, the factors contributing to abnormal alignment were analyzed using multiple logistic regression analysis. ResultsBES was significantly lower in all abnormal sagittal alignment groups, as defined by PI-LL (≥ 10°), SVA (≥4 cm), and PT (≥20°) (all P < 0.001). On multivariate analysis, BES was a contributing factor for abnormal PI-LL (P < 0.001), SVA (P = 0.001), and PT (P < 0.001). Conversely, a decrease in appendicular and trunk relative SMM index did not statistically affect abnormal spinal sagittal alignment. ConclusionsBES was associated with changes in spinal sagittal alignment; however, SMM, which is often used for diagnosing sarcopenia, did not affect spinal sagittal alignment.

Effects of a workplace exercise program on physical capacity and lower back symptoms in hospital nursing assistants: a randomized controlled trial.

Considering the relevance of muscle strength for sustaining good musculoskeletal health among workers who perform physically demanding work, the aim of this study was to evaluate the effectiveness of a therapeutic exercise program on muscle strength and low back symptoms among hospital nursing assistants. One hundred and twenty-nine nursing assistants filled out a questionnaire on personal, occupational information and health status, which allowed the identification of workers able to exercise. Ninety participants were randomly allocated to an intervention and a reference group. The therapeutic exercise program (TEP) lasted 12weeks and included warm-up, strengthening and stretching exercises. Muscle strength of trunk flexors and trunk extensors, hamstring flexibility, and low back symptoms were evaluated before and after the intervention period by two blinded assessors. The comparison between groups was carried out using Mann-Whitney and χ2 tests at a significance level of 0.05. The average participation in the exercise program was 17.5 sessions. Results showed increased trunk flexors muscle strength (p = 0.002; effect size: 0.77), improved pressure pain threshold for dorsal longissimus (p = 0.001; effect size > 0.8), and reduced low back symptoms (p = 0.002; OR = 6.25). No differences between groups were identified for back extensor muscle strength or flexibility. The exercise program applied is a feasible intervention which resulted clinically relevant results for nursing assistants' musculoskeletal health expressed through trunk flexors muscle strength improvement and low back symptoms control among nursing assistants. This RCT brings contribution to the Occupational Health field as the exercise program applied resulted in clinically relevant results for nursing assistants' musculoskeletal health. This study brings contribution especially for low-income and middle-income countries where low back pain and disability can be considered more severe as adequate resources to address the problem are scarce. Thus, we must highlight the importance of low-cost preventive strategies, like exercise programs carried out in hospital settings to avoid the progress of disability among active nursing personnel.

Exercise Therapy For Bone Health: Translation To Clinical Practice

We previously reported that high-intensity resistance and impact training (HiRIT) is safe and improves risk factors for osteoporotic fracture in postmenopausal women and older men with low bone mass under trial conditions (LIFTMOR and LIFTMOR-M trials). We have now established a translational research Clinic implementing HiRIT in practice alongside systematic longitudinal monitoring of musculoskeletal and functional outcomes to determine effectiveness and feasibility as osteoporosis prevention and therapy in the ‘real world’. PURPOSE: The aim of the current report is to present 4 year outcomes from the Clinic. METHODS: All Clinic clients undergo testing for height, weight, spine (LS), total hip (TH) and femoral neck (FN) bone mineral density (BMD), lean and fat mass, back extensor strength (BES), and functional indices of fall risk at their baseline visit, and annually thereafter. Twice-weekly supervised HiRIT with balance training and a dietary consult is provided. Compliance and injuries are comprehensively monitored. In the absence of a control group, program effectiveness is determined from one-sample t-tests of percent change from baseline. RESULTS: We report outcomes from 275 clients (94.9% female) who have completed a minimum of 12 months HiRIT (63.6±7.1 yrs, 162.3±6.8 cm, 60.6±10.0 kg, LS T-score -2.0±1.1, FN T-score -2.0±0.7, compliance 69.1±39.6%). 70 clients were on bone medications at baseline but only 18 at follow-up. Improvement was observed in weight (0.8±3.8%, P<0.0001), LS (2.2±5.1%, P<0.0001), TH (1.0±3.7%, P<0.0001) and FN BMD (1.4±4.8%, P<0.0001), lean mass (2.3±5.5%, P<0.0001), fat percent (-4.5±10.7%, P<0.0001), functional reach (7.2±13.4%, P<0.0001), timed up and go (-9.8±12.0%, P<0.0001), tandem walk (-20.6±35.1%, P<0.0001), sit to stand (-9.9±15.9%, P<0.0001), BES (20.6±35.1%, P<0.0001), and kyphosis (5.1±54.8%, P<0.05). Clients increased daily dietary calcium (23±67%, P<0.0001) and total calcium (19±68%, P<0.0001). 20 injuries were sustained in a total of 31,483 training sessions, the majority being minor muscle strains. CONCLUSION: We show that, when supervised in clinical practice, an evidence-based, targeted, high-intensity resistance and impact training program is safe and highly effective osteoporosis therapy for older men and women with low bone mass.

Use It Or Lose It: What Happens To Bone When High-Intensity Exercise Ceases Or Continues?

The LIFTMOR trial was the first to show a high-intensity resistance and impact training program (HiRIT) was safe and efficacious for improving bone and physical function in postmenopausal women with low to very low bone mass. While results were promising, the long-term efficacy and safety of HiRIT outside an RCT setting was unknown. PURPOSE: The primary aim of the current study was to evaluate the effects of continuing or ceasing HiRIT on bone mineral density (BMD) and physical function of LIFTMOR trial participants. METHODS: We report a retrospective observational study of LIFTMOR trial participants. Three years after completion of the LIFTMOR trial, participants in the HiRIT arm of the trial underwent a single testing session. Participants were allocated to one of two groups according to either ongoing HiRIT participation (compliance >25%; HiRIT-HiRIT), or cessation of HiRIT (HiRIT-CON) after LIFTMOR. The LIFTMOR testing protocol was employed, including; BMD at the lumbar spine (LS) and femoral neck (FN), back extensor strength (BES), lower extremity strength (LES), functional reach test (FRT), timed up-and-go test (TUG), five times sit-to-stand (FTSTS) and maximal vertical jump (VJ). Data were analysed using repeated measures ANCOVA comparing final LIFTMOR outcomes to 3 year outcomes. RESULTS: Twenty-three women (HiRIT-HiRIT, n = 7; 64 ± 4 yr, 159.4 ± 6.5 cm, 67.0 ± 7.2 kg and HiRIT-CON, n = 16; 65 ± 4 yr, 161.8 ± 5.9 cm, 61.9 ± 9.5 kg) participated in follow-up testing 3.2 ± 0.6 yrs post-LIFTMOR. There were no characteristic differences between the follow up sample and the LIFTMOR sample at baseline. Significant ongoing gains in BMD were apparent in HiRIT-HiRIT compared with HiRIT-CON at the LS (8.63 ± 5.29% vs 2.18 ± 5.65%, p = 0.042) and FN (3.67 ± 4.45% vs 2.85 ± 5.79%, p = 0.014), while the HiRIT-CON group maintained BMD benefits from the LIFTMOR intervention. Between-group differences in functional outcomes favoured HiRIT-HiRIT but did not reach significance. No injuries were reported. CONCLUSION: Postmenopausal women with low bone mass continuing HiRIT over a 4 year period continued to improve bone mass, while those ceasing HiRIT maintained the gains achieved from 8 months of HiRIT 3 years previously. HiRIT exercise appears to be a highly effective therapy to reduce risk of osteoporotic fracture by improving bone mass.

Comparison of muscle strength and bone mineral density in healthy postmenopausal women. A cross-sectional population study

In this cross-sectional population study with 78 healthy 0.5-5 years postmenopausal, 49-55 year old females a significant simple linear correlation between lumbar spine LII-LIV bone mineral density and adjacent back extensor and flexor isometric muscle strength was found. With the stepwise multiple linear regression analyses the most significant predictors for lumbar spine LII-LIV and femoral neck bone mineral density were weight (partial R2) (R2 = 0.197, p = 0.0001; R2 = 0.157, p = 0.0009) and age (R2 = 0.056, p = 0.0205; R2 = 0.036, p = 0.0708). Height and isometric muscle strength and endurance of muscles were not significant predictors. Weight and age were the most significant predictors also for isometric muscle strength. The mobility of spine, body fat content and anaerobic threshold had no correlation on bone mineral density.

Impact of sagittal spine-pelvis-leg alignment and muscle strength on quality of life and low back pain in rural Japanese community- dwelling middle-aged and elderly persons.

Lower limb compensation for spinal sagittal malalignment and its impact on quality of life (QOL) and low back pain (LBP) have not been well studied. To clarify postural compensation and the impact of spinal and lower limb sagittal alignment and muscle strength on QOL and LBP in persons > 50 years old. In this cross-sectional study, 122 rural community-dwelling, healthy adults (56 males, 66 females; average age 71.1 years; age range, 52-88 years) underwent assessments of QOL (36-Item Short-Form Health Survey; SF-36), LBP (Roland-Morris Disability Questionnaire; RDQ), thoracic kyphosis (TK), lumbar lordosis (LL), sacral inclination (SI), grip strength, lower limb strength, and back extensor strength (BES). On univariate and multivariate analyses, variables that correlated with QOL and the RDQ were identified. LL was moderately correlated with SI and weakly correlated with the knee flexion angle (KFA). LL, KFA, C7-L5D, and BES were correlated with SF-36 subscales and the RDQ. KFA contributed to the physical component summary of the SF-36. Female sex and BES contributed to the RDQ. Knee flexion compensated for lumbar kyphosis, but affected physical QOL scores negatively; BES was the most reliable contributor to QOL and the RDQ.

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.

Effect of eldecalcitol on muscle function and fall prevention in Japanese postmenopausal women: A randomized controlled trial

BackgroudExercises and vitamin D interventions have shown to improve muscle function and balance, and prevent falls in postmenopausal healthy women and in patients with osteoporosis. However, the effects of eldecalcitol on these factors remain undetermined. The present open-label, randomized, controlled study aimed to investigate the effects of eldecalcitol treatment in reducing falls in postmenopausal women, and improving muscle function and balance. MethodsThe study population included 226 Japanese postmenopausal women with osteoporosis. Patients were randomly divided into two groups on the basis of treatment with or without eldecalcitol (0.75 μg/day). Treatment continued for 6 months. Participants in both groups were instructed to perform back extensor muscle exercise. Isometric back extensor and leg extensor strength, grip power, ten-meter walking speed, timed up and go test and time of single leg standing were measured at baseline and 24 weeks. Patients were asked to record the number of falls during the 24-week period. ResultsThe percentage increase in average bilateral quadriceps muscle strength was significantly higher in the eldecalcitol group compared with the non-eldecalcitol group (right, p = 0.041; left, p = 0.042). In contrast, there were no significant differences in the strength of back muscles and grip power and the parameters of balance and walking abilities between the groups. There was no significant difference in the number of falls between the groups. ConclusionsA 24-week intervention of eldecalcitol improves the strength of the quadriceps muscles in postmenopausal women with osteoporosis. However, eldecalcitol neither improve balance and walking abilities nor reduce the number of falls.

Trunk Muscle Activation Patterns Differ Between Those With Low and High Back Extensor Strength During a Controlled Dynamic Task.

It is proposed that reduced function in one of the spinal systems (active, passive, and neural) outlined by Panjabi could increase the risk of experiencing a low back injury (LBI). Also proposed is that reduced function in any one system can be compensated for by adjusting the time-varying recruitment of trunk muscles. This study addressed whether those with reduced active system function (WEAK), measured as back extensor strength, would have different trunk muscle activation patterns than those with higher function (STRONG), and secondly whether this relationship would be modified following recovery from a LBI. Sixty men participated, 30 recently recovered from LBI (rLBI, 4–12 weeks post injury) and 30 who had not had a LBI in the last year (ASYM). ASYM and rLBI participants were separated into STRONG and WEAK sub-groups if their isometric back extensor strength was above or below their group median, respectively. Trunk electromyograms from 24 muscle sites were recorded during a highly controlled horizontal transfer task. Principal component analysis captured key muscle activation patterns (amplitude and temporal); then analysis of variance models tested for strength or group*strength effects on these patterns consistent with the two main objectives. Significant strength, or group by strength effects were found for 3/4 electromyographic comparisons. In general, the WEAK group required higher activation amplitudes of abdominal and back extensor muscles, and greater temporal responsiveness of back extensor muscles only to the changing external moments than those who were STRONG. Group by strength interactions found that participants in the rLBI group had greater differences between WEAK and STRONG participants for overall muscle activation amplitudes in both abdominal and back extensor muscles. This increase in muscle activation was interpreted as compensation for lower maximum force properties whereas the increased temporal responsiveness captured a greater need to modify the agonist back extensors muscle activation patterns only in response to changes in the dynamic moments. Interactions captured that the recent experience of pain (rLBI) modified the magnitude of adjustment in muscle activation patterns potentially adapting to an increased risk of instability (painful flare) events associated with a deficit (lower strength) of the active system.

Reliability and validity of three isometric back extensor strength assessments with different test postures.

ObjectiveTo compare the test-retest reliability and validity of three simple maximal isometric back extensor strength (BES) assessment protocols with different test postures, and to recommend an optimal clinical protocol to quantify BES.MethodsAsymptomatic adults, aged over 45 years, were assessed for maximal isometric BES using external fixation of dynamometers, with the subject in standing, prone and sitting positions, respectively. Measurements were repeated at a one-week interval to examine test-retest reliability. Validation was performed by comparing with results obtained from isokinetic dynamometer assessments.ResultsOut of a total of 60 included participants, intra-class correlation coefficients (ICC) were 0.92, 0.93 and 0.90 in standing, prone and sitting positions, respectively. Correlation analyses revealed acceptable convergent validity in the standing and prone position (r = 0.50 and 0.54, respectively), whereas tests conducted in the sitting position showed a relatively low validity (r = 0.32). Among the three protocols, measurement error was lowest in the prone position.ConclusionsMaximal isometric BES assessment in the prone position was shown to be the most reliable and valid protocol, and may be considered the preferred option for assessing BES in clinical practice.

The effects of short-term back extensor strength training in postmenopausal osteoporotic women with vertebral fractures: comparison of supervised and home exercise program.

To compare the effects of a 6-week supervised or home-based program of back-strengthening exercise on spinal pain, back extensor strength, trunk-arm endurance, kyphosis, functional mobility, and QoL in osteoporotic postmenopausal women with vertebral fractures. The study was designed as a randomized controlled clinical trial. Sixty osteoporotic postmenopausal women with vertebral fracture (mean age 60.3 ± 9.3years) were included in the study. Subjects were randomly assigned into three groups (supervised program, home-based program, or control), each consisting of 20 subjects. The subjects underwent the 6-week exercise program which included strengthening exercise for the back extensor muscles. They performed three sets of 8, 10, or 12 repetitions for each of the exercises, biweekly ascending, three times per week. Spinal pain, back extensor strength, trunk and arm endurance, kyphosis, functional mobility, and QoL were measured at baseline and at the end of the exercise program. Statistically significant improvements were demonstrated on spinal pain, muscle strength and endurance, functional mobility, and QoL for the supervised exercise program compared with control and home-based exercise groups (p < 0.01). Home-based exercise program did not provide a significant improvement compared with the control group except for mobility parameters of QoL. Six-week supervised back extensor strengthening training is superior to home-based program in terms of spinal pain, back extensor muscle strength, trunk endurance, functional mobility, and QoL for postmenopausal osteoporotic women with vertebral fractures.

Bone-targeted Exercise For Older Men With Osteopenia And Osteoporosis: LIFTMOR For Men Trial Preliminary Findings

PURPOSE The LIFTMOR (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation) for Men trial was designed to compare the effects of 2 novel bone-targeted exercise programs on risk factors for falls and fracture in men with low bone mineral density (BMD). METHODS LIFTMOR for Men is a 3-arm, 8-month, semi-randomised, intervention trial. Men ≥50 years of age with low BMD, screened for conditions and medications known to affect bone, were recruited. Eligible participants were randomised to 2/week, supervised high-intensity resistance and impact training (HiRIT) or bioDensity (bD) machine-based isometric exercise. Intervention responses are compared with those of a self-selected, non-randomised control (CON) sample of age-matched men following their habitual lifestyles. Outcomes at baseline and follow-up include: anthropometry; DXA-derived lumbar spine (LS) and femoral neck (FN) BMD; physical function (back extensor strength [BES], lower extremity strength [LES], timed-up-and-go [TUG], and 5-times sit-to-stand [STS]); and safety and compliance. Per-protocol analyses of preliminary outcomes were conducted using repeated measures ANCOVA, controlling for age, calcium consumption, prior physical activity, and initial values for BMD [adjusted mean change ± SE and adjusted p values are presented]. RESULTS 93 men (67.1±7.5yr; 82.1±11.6kg; 175.2±6.7cm) with low BMD (FN T-score -1.6±0.6) were recruited, and designated CON (n=26) or randomly assigned to HiRIT (n=34) or bD (n=33). To date, 67 have completed the study and are included in these preliminary findings (21 CON; 24 HiRIT; 22 bD). Compliance is 75.6±17.9% for HiRIT and 81.1±12.1% for bD (NS). Between-group differences have appeared in several outcome measures but only the improvement in LS BMD (HiRIT 0.049±0.01g/cm2 vs CON 0.013±0.01g/cm2; p=0.01) and STS (HiRIT 1.6±0.3s vs bD 0.8±0.3s; p=0.01) have reached significance. Within-group improvements have been observed for LS and FN BMD in both HiRIT and bD, all functional outcomes for HiRIT (all p<0.05), and in LES, TUG, and STS for bD (all p<0.05). There have been no adverse events. CONCLUSION Although preliminary, findings suggest that both novel bone-targeted exercise programs improved BMD and physical function in older men with osteopenia and osteoporosis. Data collection is ongoing.

Effect of treatment on back pain and back extensor strength with a spinal orthosis in older women with osteoporosis: a randomized controlled trial

SummaryThe treatment effect of an activating spinal orthosis on back pain and back extensor strength was compared to a training group and to a control group. Between the groups, there was no significant difference in back pain, back extensor strength, or kyphosis index after the 6 months of treatment.PurposeThe aim of this study was to study the effect of treatment with an activating spinal orthosis on back pain, back extensor strength, and kyphotic index. Our hypothesis was that an activating spinal orthosis may be an alternative treatment to decrease back pain and increase back extensor strength.MethodsA total of 113 women aged ≥ 60 years with back pain and osteoporosis, with or without vertebral fractures, were randomized to three groups: a spinal orthosis group, an equipment training group, and a control group. All three groups were examined at baseline and followed up after 3 and 6 months. Statistical analyses were performed with a mixed model for repeated measures according to intention to treat (ITT) and per protocol (PP).ResultsA total of 96 women completed the study. Between the groups, there was no significant difference in baseline characteristics. Comparison between groups showed no significant difference in back pain, back extensor strength, or kyphosis index at the follow-up after 6 months according to ITT and PP analyses. Analysis in each group showed that the back extensor strength had increased by 26.9% in the spinal orthosis group, by 22.1% in the exercise training group and by 9.9% in the control group.ConclusionsSix months’ treatment by an activating spinal orthosis showed no significant difference in back pain, back extensor strength, or kyphosis index between the three groups. In the spinal orthosis group, present back pain decreased slightly and back extensor strength increased by 26.9% which indicates that the spinal orthosis may become an alternative training method.Clinicaltrials.com ID: NCT03263585

Effects of a Complex Strength-Training Program on Athletic Performance of Junior Female Handball Players.

To analyze the effects of complex strength training on explosive muscle performance of junior female handball players. Subjects were arbitrarily divided between an experimental group (n = 14) and a control group (n = 14). Training sessions and matches were performed together, but during the 10-wk intervention, the experimental group replaced part of the regular regimen with complex strength training. Measures assessed in both groups before and after the intervention included running times over 5, 10, 20, and 30m; change-of-direction tests (T-half agility test and modified Illinois test); repeated shuttle sprint ability and repeated change-of-direction tests; jumping (squat, countermovement, countermovement with aimed arms, and 5-jump test); static and dynamic balance; back-extensor strength; and 1-repetition-maximum half-squat. The intervention yielded increases in sprint (10m 11.7%), change-of-direction performance (T-half 5.1%, modified Illinois 4.2%), jumping (squat P < .01, 19%; countermovement P < .01, 20.3%; countermovement aimed arms P < .01, 19.3%; 5-jump P < .05, 15.2%), and 1 of 4 repeated-sprint scores (best time P < .05, 5.9%). However, repeated-sprint T-test and balance scores were unchanged. Complex strength training develops abilities important to handball performance.

Lumbar Extensor Muscle Size and Isometric Muscle Strength in Women with Symptomatic Lumbar Degenerative Diseases.

Study DesignA cross-sectional design.PurposeTo determine the characteristics of lumbar extensor muscle (LEM) size and isometric muscle strength and examine their correlations in women with lumbar degenerative diseases (LDDs).Overview of LiteratureMany studies have evaluated the relationship between muscle size and strength, but the results have been controversial.MethodsSeventy-four female patients (mean age, 66 years) who consecutively underwent posterior lumbar interbody fusion (L1–S1) were recruited. The cross-sectional area (CSA) of the back extensor muscles was measured between L1–2 to L5–S1, and the total sum of the CSAs at each disc level was calculated. Back extensor muscle strength was evaluated using a MedX lumbar extension machine. The Oswestry Disability Index (ODI, 0–100) and Visual Analog Scale (VAS, 0–10) of lower back pain were determined.ResultsThe mean CSAs of the LEM at each level (L1/2–L5/S1) and the total sum were 34.3, 36.3, 35.1, 31.4, 21.9, and 156.2 cm2, respectively. The mean isometric strength at each angle (range, 0°–72°) was 32.5, 50.1, 72.0, 88.7, 100.7, 112.2, and 126.2 ft-lb, respectively. The mean ODI and VAS scores were 54.6 and 6.6, and the mean body weight and body mass index (BMI) were 59.9 kg and 24.9 kg/m2, respectively. The CSAs of the upper lumbar level (L1–4) and the total sum of the CSAs were associated with isometric strength, which was negatively correlated with patients’ age and ODI and positively associated with body weight and BMI, mainly at higher lumbar flexion angles (48°–72°).ConclusionsIn women with LDD, LEM sizes of the upper lumbar levels (L1–4) were larger than those of the lower levels (L4–S1) and were positively associated with muscle strength. The upper lumbar levels in patients with LDDs appear to play a compensatory role when degenerative lesions are present in the lower lumbar levels.

Kekuatan Otot dan Kualiti Hidup dalam Kalangan Dewasa Malaysia Berisiko Keretakan Osteoporotic Rendah dan Sederhana hingga Tinggi

Reduced muscle strength and quality of life (QoL) has an impact on adults at risk of osteoporotic fractures. Muscle strength and QoL among Malaysian adults at risk of osteoporotic fractures is not known. The aim of our study was to examine muscle strength and QoL status and its relationship among adults at low and moderate to high risk of osteoporotic fractures. In this cross-sectional study, we recruited 27 men and 78 women with mean age 69.3 ± 8.5 years from Orthopaedic Clinic, Hospital Canselor Tuanku Muhriz Universiti Kebangsaan Malaysia. A 10-year probability of major osteoporotic fractures were calculated according to WHO fracture risk assessment tool (FRAX) with femoral neck BMD (cut-point 10%). Participants were categorized as low and moderate to high risk of osteoporotic fractures based on FRAX results. Back extensor muscle strength (BES) and dominant hand grip strength (HGS) was measured using a load cell system and a hand dynamometer respectively. European QoL questionnaire (EQ5Dvas) was used to measure QoL. Multiple linear regression was performed with QoL as a dependent variable and back extensor muscle strength and hand grip strength as the independent variables. Approximate 40% of adults were categorized into moderate to high risk of osteoporotic fractures. The mean values among the low and moderate to high risk of osteoporotic fractures for QoL was 80.5 ± 13.2 and 76.9 ± 16.9 (p = 0.77); hand grip strength was 25.7 ± 17.3 and 20.6 ± 5.5 kg (p < 0.001) and back extensor strength was 25.0 ± 7.0 and 18.9 ± 9.5 Newton (p < 0.01) respectively. Hand grip muscle strength appeared to be a determinant of QoL and accounted for 5.8% of the total variance. Improved muscle strength may lead in better QoL among adults at risk of osteoporotic fractures. DOI : http://dx.doi.org./10.17576/JSKM-2018-31

Back Extensor Muscle Function and Osteoporotic Vertebral Fractures: A Review

Osteoporotic vertebral fractures (OVFs) are prevalent among adults with osteoporosis. Alteration in back extensor muscle function may be one of the predisposing factors of OVFs. It is vital to identify the relationship of back extensor muscle (BEM) function and OVFs to facilitate clinical management. This review presents the current understanding of a relationship between OVFs and BEM function included BEM strength, architecture, endurance and motor recruitment. After screening and limiting the search for age, and kind of BEM function and spine morphology, 33 articles were identified using PubMed, Medline, Sciences Direct, Springer link and a review of reference lists. An association between osteoporotic vertebral fractures and decline in BEM function was existed but not directly. Further prospective and larger randomized control trial of research on BEM function and OVFs are required to ensure an efficient clinical management.

Effects of Different Types of Exercise on Body Composition, Muscle Strength, and IGF-1 in the Elderly with Sarcopenic Obesity.

To investigate the influence of resistance training (RT), aerobic training (AT), or combination training (CT) interventions on the body composition, muscle strength performance, and insulin-like growth factor 1 (IGF-1) of patients with sarcopenic obesity. Randomized controlled trial. Community center and research center. Sixty men and women aged 65-75 with sarcopenic obesity. Participants were randomly assigned to RT, AT, CT, and control (CON) groups. After training twice a week for 8weeks, the participants in each group ceased training for 4weeks before being examined for the retention effects of the training interventions. The body composition, grip strength, maximum back extensor strength, maximum knee extensor muscle strength, and blood IGF-1 concentration were measured. The skeletal muscle mass (SMM), body fat mass, appendicular SMM/weight %, and visceral fat area (VFA) of the RT, AT, and CT groups were significantly superior to those of the CON group at both week 8 and week 12. Regarding muscle strength performance, the RT group exhibited greater grip strength at weeks 8 and 12 as well as higher knee extensor performance at week 8 than that of the other groups. At week 8, the serum IGF-1 concentration of the RT group was higher than the CON group, whereas the CT group was superior to the AT and CON groups. Older adults with sarcopenic obesity who engaged in the RT, AT, and CT interventions demonstrated increased muscle mass and reduced total fat mass and VFA compared with those without training. The muscle strength performance and serum IGF-1 level in trained groups, especially in the RT group, were superior to the control group.

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.