Objective The purpose of this study was to determine if multifidi size and/or intramuscular fat were associated with self-reported and performance-based physical function in older adults with and without chronic LBP. Design Case-control study Setting Individuals participated in a standardized evaluation in a clinical laboratory and underwent magnetic resonance imaging (MRI) of the lumbar spine at a nearby facility. Patient Sample A volunteer sample of 106 community-dwelling older adults, aged 60-85 years, with (n=57) and without (n=49) chronic LBP were included in this secondary data analysis. Intervention Average right-left, L5 multifidi relative, i.e. total, cross-sectional area (rCSA); muscle-fat infiltration index (MFI), i.e. a measure of intramuscular fat; and relative muscle cross-sectional area (rmCSA), i.e. total CSA minus intramuscular fat CSA, were determined from MRIs. Linear regression modeling was performed with physical function measures as the dependent variables. Age, sex, and body mass index were entered as covariates. The main effects of L5 multifidi MFI and rmCSA, as well as their interaction with group assignment, were compared as independent variables. Main Outcome Measures Short Form-36 Health Survey Physical Functioning subscale (SF-36 PFS), Timed Up and Go (TUG), gait speed, and fast stair descent performance. Results Interaction terms between L5 multifidi MFI and group assignment were found to be significant contributors to the variance explained in all physical function measures (p≤.012). Neither the main effect, nor the interaction with group assignment for L5 multifidi rmCSA, significantly contributed to the variance explained in any of the physical function measures (p>.012). Conclusions Among older adults with chronic LBP of at least moderate intensity, L5 multifidi muscle composition, but not size, may help to explain physical function.

Previous studies in older adults have identified that chronic low back pain (CLBP) is associated with slower gait speed. Given that slower gait speed is a predictor of greater morbidity and mortality among older adults, it is important to understand the underlying spatiotemporal characteristics of gait among older adults with CLBP. The purposes of this study were to determine (1) if there are differences in spatiotemporal parameters of gait between older adults with and without CLBP during self-selected and fast walking and (2) whether any of these gait characteristics are correlated with performance of a challenging walking task, e.g. stair negotiation. Spatiotemporal characteristics of gait were evaluated using a computerized walkway in 54 community-dwelling older adults with CLBP and 54 age- and sex-matched healthy controls. Older adults with CLBP walked slower than their pain-free peers during self-selected and fast walking. After controlling for body mass index and gait speed, step width was significantly greater in the CLBP group during the fast walking condition. Within the CLBP group, step width and double limb support time are significantly correlated with stair ascent/descent times. From a clinical perspective, these gait characteristics, which may be indicative of balance performance, may need to be addressed to improve overall gait speed, as well as stair-climbing performance. Future longitudinal studies confirming our findings are needed, as well as investigations focused on developing interventions to improve gait speed and decrease subsequent risk of mobility decline.

Objective. To explore potential differences in lumbar mobility between older adults with and without chronic low back pain, and to determine if lumbar mobility contributes to physical performance in both groups. We hypothesized that older adults with pain would have greater lumbar mobility impairments than pain-free peers, and that lumbar mobility would be associated with performance in both groups, with stronger relationships among those with pain.Design. Matched case-control.Setting. Research laboratory.Patients. Community-dwelling older adults, aged 60-85 years, with (N 5 54) and without (N 5 54) chronic low back pain.Methods. Inclinometer-measured maximal angles of lumbar flexion, extension, and average sidebending, as well as time to complete performance measures, Repeated Chair Rise and Timed-Up-andGo, were measured in both groups. Analysis of variance was used to explore the difference in lumbar mobility between groups. Adjusted linear regression was used to assess the independent relationship between lumbar mobility and physical function in both groups.Results. Those with pain had smaller angles of flexion (P 5 0.029) and extension (P 5 0.013). In the pain group, flexion explained 19% (P 5 0.001) and 8.9% (P 5 0.006) of the variance for time to complete the Repeated Chair Rise and Timed Up-and-Go tests, respectively. In the pain-free group, extension explained 12.7% (P 5 0.007) and 10.3% (P 5 0.008) of the variance for time to complete Repeated Chair Rise and Timed Up-and-Go tests, respectively.Conclusion. Older adults with chronic low back pain have more lumbar mobility impairments. Lumbar mobility may be a contributing factor to decreased performance in older adults. Flexion may be most important to performance in those with pain, while extension may be vital in those without pain.

Objective The purpose of this study is to identify geriatric chronic LBP subgroups based on the presence of potentially modifiable hip impairments, using Latent Variable Mixture Modeling (LVMM), and to examine the prospective relationship between these subgroups and key outcomes over time. Methods Baseline, 3-month, 6-month, and 12-month data were collected from a prospective cohort of 250 community-dwelling older adults with chronic LBP. Comprehensive hip (symptoms, strength, range of motion, and flexibility), LBP (intensity and disability), and mobility function (gait speed and Six-Minute Walk Test) examinations were performed at each timepoint. Baseline hip measures were included in LVMM; observed classes/subgroups were compared longitudinally on LBP and mobility function outcomes using mixed models. Results Regarding LVMM, a model with 3 classes/subgroups fit best. Broadly speaking, subgroups were differentiated best by hip strength and symptom presence: subgroup 1 = strong and nonsymptomatic (SNS), subgroup 2 = weak and nonsymptomatic (WNS), subgroup 3 = weak and symptomatic (WS). Regarding longitudinal mixed models, all subgroups improved in most outcomes over time. Specifically, over 12 months, the nonsymptomatic subgroups had lower LBP intensity and disability levels compared to the WS subgroup, whereas the SNS subgroup had better mobility function than the 2 “weak” subgroups. Conclusion These subgroup classifications may help in tailoring specific interventions in future trials. Special attention should be given to the WS subgroup, given their consistently poor LBP and mobility function outcomes. Impact Among older adults with chronic low back pain, there are 3 hip subgroups: “strong and nonsymptomatic,” “weak and nonsymptomatic,” and “weak and symptomatic.” People in these subgroups demonstrate different outcomes and require different treatment; proper identification will result in tailored interventions designed to benefit individual patients. In particular, people in the WS subgroup deserve special attention, as their outcomes are consistently poorer than those in the other subgroups.

Background We examined the association between improved mobility and distal health outcomes in older adults using secondary analysis of data from a cluster-randomized controlled group exercise trial. Methods Participants were 303 men and women aged ≥65 and older in 32 independent living facilities, senior apartments, and community centers who participated in 12-week group exercise interventions. Included were those who completed ≥1 follow-up phone call regarding outcomes assessment in the following year. Gait speed and 6-minute walk distance (6MWD) were assessed at baseline and immediately after 12-week interventions to determine mobility performance change status. Falls, emergency department (ED) visits, and hospitalizations were assessed monthly for 12 months following the end of interventions via interactive voice response phone calls. Incident rate ratios (IRRs) were calculated to quantify incidence of adverse outcomes with respect to mobility performance change. Results Each 0.05 m/s increase in gait speed resulted in an 11% reduction in falls (IRR = 0.89; 95% confidence interval [CI], 0.84–0.94; p < .0001); a similar decrease was seen for each 20 m increase in 6MWD (IRR = 0.89; 95% CI, 0.83–0.93; p = .0003). Those who improved gait speed had 61 falls per 1,000 person-months versus 135 in those who had no change/a decline. Those who improved 6MWD had 67 falls per 1,000 person-months versus 110 per 1,000 person-months in those who had no change/a decline. Differences in ED visits and hospitalizations were not statistically significant. Conclusion Improvements in mobility performance are associated with lower incidence of future falls. Given the exploratory nature of the findings, further investigation is warranted.