Active Trunk Extensor Contributions to Dynamic Posteroanterior Lumbar Spinal Stiffness

The relationship between driving distance and different types of contraction in core muscles in Korea elite female golfers

BACKGROUND

This study compared and examined the relationship between the concentric, eccentric, and isometric muscular contraction measurements that are commonly used to assess trunk strength and power, and the driving distance in elite female golfers. The purpose of this study was to utilize as a basis to evaluate the driving distance-related physical training program design and its efficacy.

METHODS

Eighteen female golfers from A club in Gyeonggi province are recruited. The driving distance, medicine ball throwing, isokinetic trunk flexor, and extensor strength and power, and isometric strength in the 3D electromagnetic motion analysis system were assessed. The statistical analysis adopted the Students' t-test to adjust the different units in each assessment method, and then interrelation and correlation analysis between the driving distance was conducted.

RESULTS

The result of this study is as the following: the medicine ball throwing, isokinetic trunk extensor power, isometric trunk flexor, and extensor strength, and left and right flexor and rotator strength showed high correlation with the driving distance. In the comparison between strength factors, isokinetic trunk extensor strength had a high correlation (R²=0.452), while the medicine ball throw and isokinetic trunk extensor power were reported a higher correlation in order (R²=0.740). In the overall comparison analysis, the isometric trunk left rotation, and isometric trunk extensor had an R² value of 0.893.

CONCLUSIONS

Consequently, the isometric trunk rotational strength and extensor strength had the highest correlation with the driving distance. This result can be used to design the physical fitness program for golfers.

The immediate effects of foam roller with vibration on hamstring flexibility and jump performance in healthy adults

This study aimed to determine whether foam roller with vibration (FRV) can improve hamstring flexibility and jump performance in young adults. Twenty subjects were randomly allocated into either the FRV or the foam-roller with no vibration (FRNV) groups. The vibration of the vibration foam-roller was 32 Hz. All participants completed one 10-min session on the hamstring. Active straight leg raising (ASLR) test in supine position and active knee extension (AKE) test in sitting position were performed to measure hamstring flexibility, before and immediately after the session. ASLR, AKE, and vertical jump performance test were performed before the session and immediately after the session. Analysis of covariance was used to determine statistical significance. ASLR and AKE tests were significantly different between FRV and FRNV, except the right hamstring. There was significant improvement with respect to ASLR and AKE tests after the session in FRV group. The vertical jump performance test of both groups was not significantly different after the session. FRV is more effective than FRNV for improving hamstring flexibility.

Optimizing treatment protocols for spinal manipulative therapy: study protocol for a randomized trial

BACKGROUND

Low back pain is a common and costly condition. Spinal manipulative therapy (SMT) is a treatment supported in some guidelines, although most clinical trials examining SMT report small effect sizes. Enhancing the effects of SMT requires an understanding of underlying mechanisms and a systematic approach to leverage understanding of mechanisms to create more effective treatment protocols that are scalable in clinical practice. Prior work has identified effects on spinal stiffness and lumbar multifidus activation as possible mechanisms. This project represents a refinement phase study within the context of a multi-phase optimization strategy (MOST) framework. Our goal is to identify an optimized SMT treatment protocol by examining the impact of using co-intervention exercise strategies that are proposed to accentuate SMT mechanisms. The optimized protocol can then be evaluated in confirmation phase clinical trials and implementation studies.

METHODS

A phased, factorial randomized trial design will be used to evaluate the effects of three intervention components provided in eight combinations on mechanistic (spinal stiffness and multifidus muscle activation) and patient-reported outcomes (pain and disability). All participants will receive two sessions then will be randomly assigned to receive six additional sessions (or no additional treatment) over the next three weeks with factorial combinations of additional SMT and exercise co-interventions (spine mobilizing and multifidus activating). Outcome assessments occur at baseline, and one week, four weeks, and three months after enrollment. Pre-specified analyses will evaluate main effects for treatment components as well as interaction effects.

DISCUSSION

Building on preliminary findings identifying possible mechanisms of effects for SMT, this trial represents the next phase in a multiphase strategy towards the ultimate goal of developing an optimized protocol for providing SMT to patients with LBP. If successful, the results of this trial can be tested in future clinical trials in an effort to produce larger treatment benefits and improve patient-centered outcomes for individuals with LBP.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02868034 . Registered on 16 August 2016.

Acceleration of clinician hand movements during spinal manipulative therapy

This study used an observational design to examine the kinematics of spinal manipulative therapy (SMT) by determining the acceleration characteristics of the manipulative input at the cervical, thoracic, and lumbar spinal regions. Studies of SMT have been restricted to measuring the forces that result from the manipulative input. Several studies have indicated the rate of force development is a key parameter of clinically delivered SMT. Despite this, the movement strategies employed during SMT, including acceleration, have not been directly measured. Participants (n = 29) were recruited from a private practice chiropractic clinic. A wireless accelerometer attached to the clinician's hand was used to characterize the thrust phase of the SMT treatments. Significant differences were found across each spinal region for acceleration amplitude parameters (p < 0.0001). Post-hoc analysis indicated that amplitudes significantly increased in order from thoracic to cervical to lumbar regions (p < 0.0001). Spinal level was also a significant factor in determining the temporal parameters of hand acceleration during SMT (p < 0.0005). This study provides a description of the acceleration properties of clinically delivered SMT. Consistent with that reported for SMT forces, acceleration amplitudes varied significantly across spinal regions with relatively little differences in acceleration latencies. Notably, acceleration amplitudes and latencies were not associated with each other within spinal regions. These findings indicate that changes in acceleration amplitude, rather than latency, are used to tailor SMT to individuals.

Dose optimization for spinal treatment effectiveness: a randomized controlled trial investigating the effects of high and low mobilization forces in patients with neck pain

STUDY DESIGN

Randomized controlled trial. Objective To determine if force magnitude during posterior-to-anterior mobilization affects immediate and short-term outcomes in patients with chronic, nonspecific neck pain.

BACKGROUND

The optimal dose of mobilization to effectively treat patients with neck pain is not known.

METHODS

Patients with neck pain of at least 3 months in duration (n = 64) were randomized to receive a single treatment of posterior-to-anterior mobilization applied with 30 N or 90 N of mean peak force (3 sets of 30 seconds) or a placebo (detuned laser) on the spinous process at the painful spinal level. Pressure pain threshold, pain measured with a visual analog scale (range, 0-100 mm), cervical range of motion, and spinal stiffness at the painful spinal level (measured with a custom device and normalized as a percentage of C7 stiffness) were assessed before, immediately after, and at a mean ± SD follow-up of 4.0 ± 1.8 days following treatment. Repeated-measures analysis of covariance and Bonferroni-adjusted post hoc tests determined group differences for each outcome measure after treatment and at follow-up.

RESULTS

At follow-up, the 90-N group had less pain than the 30-N group (mean difference, 11.3 mm; 95% confidence interval: 0.1, 22.6 mm; P = .048) and lower stiffness than the placebo group (mean difference, 17.5%; 95% confidence interval: 4.2%, 30.9%; P = .006). These differences were not present immediately after treatment. There were no significant between-group differences in pressure pain threshold or range of motion after treatment or at follow-up.

CONCLUSION

A specific dose of mobilization, in terms of applied force, appears necessary for reducing stiffness and potentially pain in patients with chronic neck pain. Changes were not observed immediately after mobilization, suggesting that its effects are not directly mechanical.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ( http://www.anzctr.org.au/): ACTRN12611000374965.

LEVEL OF EVIDENCE

Therapy, level 1b-.

Efficacy of segmental stabilization exercise for lumbar segmental instability in patients with mechanical low back pain: A randomized placebo controlled crossover study

Background:

Lumbar segmental stability is an important biomechanical component that influences symptoms amongst patients with Mechanical low back pain.

Aims:

To compare the efficacy of segmental stabilization exercises utilizing multifidus and transversus abdominis muscles versus a placebo treatment in patients with lumbar segmental instability.

Materials and methods:

The study was an observer-blinded randomized placebo-controlled cross-over study of 18 adults (12 men, 6 women), of mean age 22.5 ± 1.09 yrs who scored 7/13 in subjective aspects and 8/14 in objective aspects of Delphi criteria for lumbar segmental instability. The selected subjects were then randomized to receive either placebo-control (prone lying) or experimental (lumbar segmental stabilization) as a first treatment. Each treatment was followed by a wash-out period of 24 hours. Outcomes were measured four times- pre- and post- first intervention, pre- and post- second intervention. The outcome measures used were pain on Visual analogue scale, Pressure pain threshold and Joint play grading scale (0-6 scale) on that level.

Results:

Two-way analysis of variance and post-hoc analysis using Bonferonni test were used with level of significance set at p<.05 using Statistical package for social sciences version 12.0.1 for Windows. Visual analogue scale changed significantly in both the periods of intervention- in control (P =.016) and experimental (P =.000) periods. However this improvement was more significant in the experimental period. The Joint play grading scale scores improved only in the experimental condition compared to the control condition significantly. The Pressure pain threshold also improved significantly in the experimental condition (P =.000) while the changes in control condition was not statistically significant (P=.816).

Conclusion:

Segmental stabilization exercise was more effective than placebo intervention in symptomatic lumbar segmental instability.

A structured review of spinal stiffness as a kinesiological outcome of manipulation: its measurement and utility in diagnosis, prognosis and treatment decision-making

PURPOSE

To review and discuss the methods used for measuring spinal stiffness and factors associated with stiffness, how stiffness is used in diagnosis, prognosis, and treatment decision-making and the effects of manipulative techniques on stiffness.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, AMED and ICL databases was conducted. Included studies addressed one of four constructs related to stiffness: measurement, diagnosis, prognosis and/or treatment decision-making, and the effects of manipulation on stiffness. Spinal stiffness was defined as the relationship between force and displacement.

RESULTS

One hundred and four studies are discussed in this review, with the majority of studies focused on the measurement of stiffness, most often in asymptomatic persons. Eight studies investigated spinal stiffness in diagnosis, providing limited evidence that practitioner-judged stiffness is associated with radiographic findings of sagittal rotational mobility. Fifteen studies investigated spinal stiffness in prognosis or treatment decision-making, providing limited evidence that spinal stiffness is unlikely to independently predict patient outcomes, though stiffness may influence a practitioner's application of non-thrust manipulative techniques. Nine studies investigating the effects of manipulative techniques on spinal stiffness provide very limited evidence that there is no change in spinal stiffness following thrust or non-thrust manipulation in asymptomatic individuals and non-thrust techniques in symptomatic persons, with only one study supporting an immediate, but not sustained, stiffness decrease following thrust manipulation in symptomatic individuals.

CONCLUSIONS

The existing limited evidence does not support an association between spinal stiffness and manipulative treatment outcomes. There is a need for additional research investigating the effects of manipulation on spinal stiffness in persons with spinal pain.

Creation of an asymmetrical gradient of back muscle activity and spinal stiffness during asymmetrical hip extension

BACKGROUND

Low back pain is often associated with increased spinal stiffness which thought to arise from increased muscle activity. Unfortunately, the association between paraspinal muscle activity and paraspinal stiffness, as well as the spatial distribution of this relation, is unknown. The purpose of this investigation was to employ new technological developments to determine the relation between spinal muscle contraction and spinal stiffness over a large region of the lumbar spine.

METHODS

Thirty-two male subjects performed graded isometric prone right hip extension at four different exertion levels (0%, 10%, 25% and 50% of the maximum voluntary contraction) to induce asymmetric back muscle activity. The corresponding stiffness and muscle activity over bilateral paraspinal lumbar regions was measured by indentation loading and topography surface electromyography, respectively. Paraspinal stiffness and muscle activity were then plotted and their correlation was determined.

FINDINGS

Data from this study demonstrated the existence of an asymmetrical gradient in muscle activation and paraspinal stiffness in the lumbar spine during isometric prone right hip extension. The magnitude and scale of the gradient increased with the contraction force. A positive correlation between paraspinal stiffness and paraspinal muscle activity existed irrespective of the hip extension effort (Pearson correlation coefficient, range 0.566-0.782 (P<0.001)).

INTERPRETATION

Our results demonstrate the creation of an asymmetrical gradient of muscle activity and paraspinal stiffness during right hip extension. Future studies will determine if alterations in this gradient may possess diagnostic or prognostic value for patients with low back pain.

A novel biomechanical device improves gait pattern in patient with chronic nonspecific low back pain

STUDY DESIGN

A retrospective study on patients with chronic nonspecific low back pain (NSLBP).

OBJECTIVE

To describe the gait stride characteristics of patients with chronic NSLBP, and to examine the effect of a novel biomechanical device on the gait stride characteristics of these patients.

SUMMARY OF BACKGROUND DATA

Patient with NSLBP alters their gait patterns. This is considered a protective mechanism as patients try to avoid extensive hip and spine ranges of motion and minimize forces and moments acting on the body. In addition, there are changes in the neuromuscular control system in patients with LBP that could possibly be attributed to the effects of pain on motor control.

METHODS

Nineteen patients underwent a gait test, using an electronic walkway, at baseline and after 12 weeks of treatment. Spatiotemporal parameters were used to identify changes in gait pattern. A novel biomechanical device comprised of 4 modular elements attached to foot-worn platforms was used in the study. The modules are 2 convex shaped biomechanical elements attached to each foot, one is located under the hindfoot region and the other is located under the forefoot region. The device was individually calibrated to each patient. The patients were instructed to walk with the calibrated biomechanical device on a daily basis for a period of 12 weeks.

RESULTS

Significant differences were found at baseline and after 12 weeks in normalized velocity (P = 0.03), cadence (P < 0.01), left normalized step length (P = 0.02), right normalized step length (P = 0.02), right swing (P < 0.01), right stance (P < 0.01), left single limb support (P = 0.01), left double limb support (P = 0.02), and right double limb support (P = 0.02).

CONCLUSION

Patients with NSLBP treated with the novel biomechanical device for 3 months increased walking speed through longer step length and eliminated asymmetrical differences.

Trunk muscle onset and cessation in golfers with and without low back pain

The knowledge of the onset and cessation timing of the paraspinal muscles that surround the lumbar spine is an important area of research for the understanding of low back pain. This study examined the timing of the erector spinae and external oblique muscle activity in a group of golfers with and without low back pain. The study compared the results of surface electromyography measurements for two groups of golfers. Twelve male golfers who had reported a mild or greater level of pain in the lower back that was experienced while playing golf were examined. A further fifteen male golfers who had reported no history of lower back pain in the previous 12 months were recruited as controls. The results showed that the low-back-pain golfers switched on their erector spinae muscle significantly in advance of the start of the backswing. This finding was not evident in the group who did not have low back pain symptoms. Low-back-pain golfers, therefore, may use the erector spinae muscle as a primary spinal stabiliser instead of the stronger deeper muscles such as transversus abdominis and multifidus. These results may have important implications for conditioning programmes for golfers with low back pain.

The effect of abdominal stabilization contractions on posteroanterior spinal stiffness

STUDY DESIGN

Intrasubject controls with randomized intervention order.

OBJECTIVE

To quantify the immediate change in posteroanterior (PA) spinal stiffness produced by different combinations of trunk muscle contraction.

SUMMARY OF BACKGROUND DATA

The abdominal hollow and the abdominal brace are 2 different combinations of trunk muscle contractions that are commonly prescribed to increase spinal stability. Unfortunately, the immediate effect of these different contractions on spinal stiffness (one indicator of spinal stability) has not yet been quantified directly.

METHODS

Twenty-eight asymptomatic subjects were taught abdominal hollow and brace contractions then performed them in a randomized order framed by periods of rest. Surface electromyography and B-mode ultrasound confirmed that all contractions were performed appropriately. During each test condition (hollow, brace, and rest), a noninvasive indentation technique was used to quantify PA spinal stiffness. A repeated measures analysis of variance was used to assess the significance of changes in the PA spinal stiffness between test conditions.

RESULTS

Both the abdominal hollow and abdominal brace contractions increased PA spinal stiffness significantly when compared with the rest condition (P < 0.001). When the abdominal hollow and brace contractions were compared with each other, the abdominal brace contraction produced significantly greater PA spinal stiffness (P < 0.05).

CONCLUSION

In asymptomatic subjects, the abdominal brace contraction provided an immediate PA stiffening effect that was significantly greater in magnitude when compared with conditions of rest and abdominal hollowing. These findings may allow clinicians to better match commonly prescribed contraction-based interventions with specific patient needs. Future work is required to assess the long-term effect of repeated abdominal brace and hollow contractions on PA spinal stiffness and low back pain.

Muscular contributions to dynamic dorsoventral lumbar spine stiffness

Spinal musculature plays a major role in spine stability, but its importance to spinal stiffness is poorly understood. We studied the effects of graded trunk muscle stimulation on the in vivo dynamic dorsoventral (DV) lumbar spine stiffness of 15 adolescent Merino sheep. Constant voltage supramaximal electrical stimulation was administered to the L3-L4 interspinous space of the multifidus muscles using four stimulation frequencies (2.5, 5, 10, and 20 Hz). Dynamic stiffness was quantified at rest and during muscle stimulation using a computer-controlled testing apparatus that applied variable frequency (0.46-19.7 Hz) oscillatory DV forces (13-N preload to 48-N peak) to the L3 spinous process of the prone-lying sheep. Five mechanical excitation trials were randomly performed, including four muscle stimulation trials and an unstimulated or resting trial. The secant stiffness (k (y) = DV force/L3 displacement, kN/m) and loss angle (phase angle, deg) were determined at 44 discrete mechanical excitation frequencies. Results indicated that the dynamic stiffness varied 3.7-fold over the range of mechanical excitation frequencies examined (minimum resting k (y) = 3.86 +/- 0.38 N/mm at 4.0 Hz; maximum k (y) = 14.1 +/- 9.95 N/mm at 19.7 Hz). Twenty hertz muscle stimulation resulted in a sustained supramaximal contraction that significantly (P < 0.05) increased k (y) up to twofold compared to rest (mechanical excitation at 3.6 Hz). Compared to rest, k (y) during the 20 Hz muscle stimulation was significantly increased for 34 of 44 mechanical excitation frequencies (mean increase = 55.1%, P < 0.05), but was most marked between 2.55 and 4.91 Hz (mean increase = 87.5%, P < 0.05). For lower frequency, sub-maximal muscle stimulation, there was a graded change in k (y), which was significantly increased for 32/44 mechanical excitation frequencies (mean increase = 40.4%, 10 Hz stimulus), 23/44 mechanical excitation frequencies (mean increase = 10.5%, 5 Hz stimulus), and 11/44 mechanical excitation frequencies (mean increase = 4.16%, 2.5 Hz stimulus) when compared to rest. These results indicate that the dynamic mechanical behavior of the ovine spine is modulated by muscle stimulation, and suggests that muscle contraction plays an important role in stabilizing the lumbar spine.