Reliability of measurements of endurance time, electromyographic fatigue and recovery, and associations to activity limitations, in patients with lumbar disc herniation

CrowbarLimbs: A Fatigue-Reducing Virtual Reality Text Entry Metaphor

Text entry remains challenging in virtual environments, where users may quickly experience physical fatigue in some body parts using existing methods. In this paper, we propose "CrowbarLimbs," a novel virtual reality (VR) text entry metaphor with two deformable extended virtual limbs. By using a crowbar-like metaphor and placing the virtual keyboard at a user-preferred location based on the user's physical stature, our method can assist the user in placing their hands and arms in a comfortable posture, thus effectively reducing the physical fatigue in various body parts, such as hands, wrists, and elbows. In an initial user study, we found that CrowbarLimbs achieved text entry speed, accuracy, and system usability comparable to those of previous VR typing methods. To investigate the proposed metaphor in more depth, we further conducted two additional user studies to explore the ergonomically user-friendly shapes of CrowbarLimbs and virtual keyboard locations. The experimental results indicate that the shapes of CrowbarLimbs have significant effects on the fatigue ratings in various body parts and text entry speed. Furthermore, placing the virtual keyboard near the user and at half their height can lead to a satisfactory text entry rate of 28.37 words per minute.

A Meta-Analysis of the Reliability of Four Field-Based Trunk Extension Endurance Tests

This meta-analysis aimed to estimate the inter- and intra-tester reliability of endurance measures obtained through trunk extension field-based tests and to explore the influence of the moderators on the reliability estimates. The reliability induction rate of trunk extension endurance measures was also calculated. A systematic search was conducted using various databases, and subsequently 28 studies were selected that reported intraclass correlation coefficients for trunk extension endurance measures. Separate meta-analyses were conducted using a random-effects model. When possible, analyses of potential moderator variables were carried out. The inter-tester average reliability of the endurance measure obtained from the Biering-Sorensen test was intraclass correlation coefficient (ICC) = 0.94. The intra-session reliability estimates of the endurance measures recorded using the Biering-Sorensen test, the prone isometric chest raise test, and the prone double straight-leg test were ICC = 0.88, 0.90, and 0.86, respectively. The inter-session average reliability of the endurance measures from the Biering-Sorensen test, the prone isometric chest raise test, and the dynamic extensor endurance test were ICC = 0.88, 0.95, and 0.99, respectively. However, due to the limited evidence available, the reliability estimates of the measures obtained through the prone isometric chest raise, prone double straight-leg, and dynamic extensor endurance tests should be considered with a degree of caution. Position control instruments, tools, and familiarization session demonstrated a statistical association with the inter-session reliability of the Biering-Sorensen test. The reliability induction rate was 72.8%. Only the trunk extension endurance measure obtained through the Biering-Sorensen test presented sufficient scientific evidence in terms of reliability to justify its use for research and practical purposes.

Comparison of Lower Limb and Back Exercises for Runners with Chronic Low Back Pain

INTRODUCTION

This single-blind randomized trial was conducted to compare the treatment effect of lower limb (LL) exercises versus conventional lumbar extensor (LE) and lumbar stabilization (LS) exercises in recreational runners with chronic low back pain (cLBP), because there is currently no specific protocol for managing runners with cLBP.

METHODS

Eighty-four recreational runners with cLBP were allocated to three exercise groups (LL, LE, LS) for an 8-wk intervention. Outcome measures included self-rated pain and running capability, LL strength, back muscle function, and running gait. Participants were assessed at preintervention, mid-intervention, and end-intervention; selected outcomes also followed up at 3 and 6 months. Generalized estimating equation was adopted to examine group-time interaction.

RESULTS

The LL group improved 0.949 points per time point in Patient-Specific Functional Scale (P < 0.001), which was higher than the LE (B = -0.198, P = 0.001) and LS groups (B = -0.263, P < 0.001). All three groups improved on average 0.746 points per time point in Numeric Pain Rating Scale for running-induced pain (P < 0.001). Knee extension strength increased 0.260 N·m·kg per time point (P < 0.001) in the LL group, which was higher than the LE (B = -0.220, P < 0.001) and LS groups (B = -0.206, P < 0.001). The LL group also showed a greater increase in running step length (2.464 cm per time point, P = 0.001) compared with LS group (B = -2.213, P = 0.013). All three groups improved similarly in back muscle function.

CONCLUSION

LL exercise therapy could be a new option for cLPB management given its superior effects in improving running capability, knee extension strength, and running gait.

Hip Abductor Fatigability and Recovery Are Related to the Development of Low Back Pain During Prolonged Standing

A prolonged standing exposure can identify asymptomatic adults who have a higher risk of developing clinical low back pain later in life. Hip abductor cocontraction differences can predict low back pain development during standing exposures. This study’s purpose was to determine if hip abductor strength, fatigability, and recovery during prolonged standing were related to standing-induced low back pain. Forty young, asymptomatic adults (50% female) performed two 2-hour standing sessions; a fatiguing hip abductor exercise was performed prior to 1 of the 2 standing sessions. Hip abductor strength and surface electromyography of gluteus medius and tensor fascia latae were measured. Self-reported low back pain differentiated low back pain developing (PD) and nonpain developing (NPD) groups. The PD group hip abductors fatigued before the NPD group, with similar perceived effort and force losses. Mean power frequency decreases with fatigue were similar between pain groups for all muscles measured after the fatiguing exercise. Unlike NPDs, PDs did not recover force losses after 120 minutes of standing. Hip abductor fatigability may be related to the development of low back pain in this population.

Reliability and Validity Testing of the MotionWatch 8 in Older Adults

Background and Purpose: The purpose of this pilot study was to test the reliability and validity of the MotionWatch 8 with older adults. Methods: Participants wore the MotionWatch 8 for 3 days, completed a diary of activities and the Borg Rating of Perceived Exertion (RPE) scale. Results: Evidence of reliability and validity was supported because there was no difference in daily level of activity and that recorded physical activity matched the activity counts. There was a significant difference in Borg RPE scale scores between the sedentary group (Borg RPE scale = 8.6,SD= 3.0) and those with some level of activity (Borg RPE scale = 9.9,SD= 2.3;F= 5.72,p= .02). Conclusion: The findings provide preliminary support for the reliability and validity of the MotionWatch 8 when used with older adults.

Developing a Reliable Core Stability Assessment Battery for Patients with Nonspecific Low Back Pain

STUDY DESIGN

Test-retest design.

OBJECTIVE

The objective was to examine the intrarater (test-retest) reliability of the core stability related tests and to develop a reliable core stability assessment battery.

SUMMARY OF BACKGROUND DATA

Studies suggest that core stability exercises may improve function and decrease pain in patients with nonspecific low back pain (LBP). Reliable clinical tests are required to implement adequate rehabilitation and to evaluate results of these interventions.

METHODS

The study had a test-retest design. Thirty-three different tests that might relate to core stability were identified with their mostly used protocols. Five different components of core stability including endurance, flexibility, strength, functional performance, and motor control were assessed in 38 patients with nonspecific LBP. The same testing procedure was performed again after 48 to 72 hours. Intraclass correlation coefficients (ICCs), standard error of measurement, and minimal detectable change were calculated to assess the intrarater reliability.

RESULTS

The intrarater reliability of the tests ranged from little to very high (ICC = 0.08-0.98). Partial curl-up (ICC = 0.90), lateral bridge (ICC = 0.95-0.96), trunk flexor endurance (ICC = 0.97), sit and reach (ICC = 0.98), single-legged hop (ICC = 0.98-0.97), lateral step-down (ICC = 0.93-0.92), eyes open right and left leg unilateral stance (ICC = 0.97 and 0.91) tests had the highest intrarater reliability for each core stability component.

CONCLUSION

The results indicated that the partial curl-up test (strength), side bridge and trunk flexor tests (endurance), sit-and-reach test (flexibility), single-legged hop, and lateral step-down (functional), unilateral stance test with eyes open (motor control) had very high intrarater reliability. A core stability assessment battery involving these tests can be used in patients with nonspecific LBP to assess all components of core stability.

LEVEL OF EVIDENCE

3.

Lumbar muscle fatigue and subjective health measurements in patients with lumbar disc herniation 2 years after surgery

INTRODUCTION

In this prospective study the purpose was to evaluate patients with lumbar-disc herniation regarding changes in back-muscle fatigue and subjective health measurements 2 years after surgery.

METHODS

Endurance time, EMG median frequency and ratings of lumbar-muscle fatigue and pain were measured before surgery, 4 weeks after and 2 years after surgery in 26 patients (19 men and 7 women) with lumbar-disc herniation. A modified Sørensen test was performed with concurrent recordings of electromyography from the lumbar muscles at four recording sites. The questionnaires Oswestry disability index, Roland-Morris disability questionnaire, Self-efficacy scale, SF-36, Back beliefs questionnaire, Odom and a 6-grade physical activity scale were used.

RESULTS

Two years after surgery the patients had longer endurance times (increase from 178 s to 231 s, p < 0.001), a non-significant tendency for flatter L5 slopes (decrease from -0.20 to -0.16 Hz/s, p < 0.066), higher initial median frequency (L1 increase from 58 to 64 Hz p < 0.001, L5 increase from 76 to 84 Hz p = 0.001) and improved questionnaire scores. The questionnaires Oswestry, Roland-Morris and SF-36 physical functioning correlated with the endurance time 0.69-0.93 and with L5 slope 0.01-0.93 and the highest correlations were found in women.

CONCLUSION

Both EMG and endurance time measurements are needed for evaluating fatigue in lumbar-disc herniation.