Effects of a lower extremity exercise program on gait biomechanics and clinical outcomes in children and adolescents with obesity: A randomized controlled trial

BACKGROUND

Research highlights the detrimental effects of obesity on gait biomechanics and the accompanied risk of lower-extremity skeletal malalignments, increased joint stress, pain and discomfort. Individuals with obesity typically show increased knee valgus angles combined with an increased step width. Accompanying muscular dysfunctions impede their ability to compensate for these alterations, especially in the frontal plane. To date, no studies are available, which evaluated the potential effects of an exercise program (EP) in reducing these unfavorable biomechanical changes.

RESEARCH QUESTIONS

Is a 12-week EP, which includes hip abductor and knee extensor strength exercises and fosters dynamic knee alignment, effective in positively altering gait biomechanics in children and adolescents with obesity?

METHODS

This study was a randomized controlled trial having children and adolescents with obesity assigned to an EP (n = 19) or control (n = 16) group. Pain, self-rated knee function, muscle strength and 3D gait analysis during walking and stair climbing were evaluated.

RESULTS

Results indicate that the EP was able to increase muscular strength especially in the hip abductors. In addition, children from the EP group walked with less maximum hip adduction and reduced pelvic drop during weight acceptance at follow-up. No changes were present in self-rated knee function, pain or discomfort.

SIGNIFICANCE

Even though effects were small, results indicate that an EP is an effective short-term possibility to counteract the progressive development of biomechanical malalignments of the lower extremity. Clinical parameters indicated that the program was feasible. Nonetheless, low adherence highlights the need to develop more attractive programs. CLINICAL TRIALS REG. NO: clinicaltrials.gov (NCT02545764).

Reliability of joint kinematic calculations based on direct kinematic and inverse kinematic models in obese children

BACKGROUND

In recent years, the reliability of inverse (IK) and direct kinematic (DK) models in gait analysis have been assessed intensively, but mainly for lean populations. However, obesity is a growing issue. So far, the sparse results available for the reliability of clinical gait analysis in obese populations are limited to direct kinematic models. Reliability error-margins for inverse kinematic models in obese populations have not been reported yet.

RESEARCH QUESTIONS

Is there a difference in the reliability of IK models compared with a DK model in obese children? Are there any differences in the joint kinematic output between IK and DK models?

METHODS

A test-retest study was conducted using three-dimensional gait analysis data from two obese female and eight obese male participants from an earlier study. Data were analyzed using a DK model and two OpenSim-based IK models. Test-retest reliability was compared by calculating the Standard Error of Measurement (SEM) along with similar absolute reliability measures. A Friedman Test was used to assess whether there were any significant differences in the reliability between the models. Kinematic output of the models was compared by using Statistical Parametric Mapping (SPM).

RESULTS

No significant differences were found in the reliability between the DK and IK models. The SPM analysis indicated several significant differences between both IK models and the DK approach. Most of these differences were continuous offsets.

SIGNIFICANCE

Reliability values showed clinically acceptable error-margins and were comparable between all models. Therefore, our results support the careful use of IK models in overweight or obese populations, e.g. for musculoskeletal modelling studies. The inconsistent kinematic output can mainly be explained by different model conventions and anatomical segment coordinate frame definitions.

Minimally invasive compared with traditional transgluteal approach for total hip arthroplasty: a comparative gait analysis

BACKGROUND

Minimally invasive total hip arthroplasty is purported to allow an improved and faster rehabilitation in the immediate postoperative period because of reduced soft-tissue damage compared with total hip arthroplasty performed with use of a standard approach. In the present study, a minimally invasive approach was compared with a traditional standard approach in terms of the effect on gait kinematics as demonstrated with gait analysis and electromyography.

METHODS

Twenty randomized patients who underwent a primary total hip replacement with use of a minimally invasive modified Watson-Jones approach (minimally invasive group) were compared with a group of twenty patients who underwent a total hip arthroplasty with use of a standard transgluteal Hardinge approach (standard group). All patients received the same cementless implant, inserted with use of standard instruments, and all operations were performed by a single, experienced surgeon. The patients were evaluated with use of three-dimensional gait analysis and dynamic electromyograms at three time points: preoperatively, ten days postoperatively, and twelve weeks postoperatively. Temporospatial and joint-kinematic parameters were evaluated.

RESULTS

There were no significant differences between the two groups with regard to the temporospatial variables of velocity, cadence, step length, and stride length at any tested time point. With regard to the range of motion of the operatively treated hip, the minimally invasive group had a smaller decrease at the ten-day time point in comparison with the standard group. However, this finding was not significant. The reduction in the range of motion was mainly caused by reduced hip extension. A compensatory increase in the pelvic tilt was observed in both groups. One patient in the standard group showed a positive Trendelenburg gait ten days postoperatively; it had disappeared completely at the twelve-week time point.

CONCLUSIONS

With regard to gait kinematics in the early postoperative period (three months), the present study showed no significant benefit for patients who underwent a total hip arthroplasty through a minimally invasive Watson-Jones approach in comparison with those who were managed with a standard transgluteal approach.

Spinal posture during stooped walking under vertical space constraints

STUDY DESIGN

Simultaneous spine kinematic variables in sewage workers were quantified using a two-dimensional video-based gait analysis system.

OBJECTIVES

To identify patterns of spinal posture in a population of sewage workers pushing waste matter through tunnels while walking stooped under various height constraints.

SUMMARY OF BACKGROUND DATA

Working with stooped postures is one of several occupational risk factors that have been associated with spinal disorders. However, the specific changes in spinal posture during stooped walking under various height constraints have not been documented.

METHODS

A video-based gait analysis system was used to measure spinal posture in 22 sewage workers. Angles of the cervical, thoracic, and lumbar spine in the sagittal plane were assessed during walking with five levels of height constraint, from upright walking to stooped walking under a headroom restriction of 105 cm. Correlations among gait parameters, demographic data, and clinical results were determined. Linear regression analysis was performed to examine which variables have the largest impact on the posture resulting from a given vertical height constraint when age and body height are held constant.

RESULTS

Mean angular values changed significantly with increasing headroom restrictions, with increases in cervical and thoracic extension as well as lumbar flexion. The cervical and thoracic angles were best correlated with height constraint, followed by lumbar angle and stride length. The inverse relation between cervical and thoracic angle during upright walking increased with increasing vertical space constraints, whereas the relation between the thoracic and lumbar angles decreased. Subjects with decreased abdominal muscle strength adopted a significantly more kyphotic thoracic posture when walking under headroom constraints than subjects with normal abdominal muscle strength.

CONCLUSIONS

Combined walking and pushing under vertical space constraints was associated not only with the expected increased flexion of the lumbar spine, but also with greater extension (i.e., reduced kyphosis) of the thoracic spine.

Load-dependence of fatigue related changes in tremor around 10 Hz

OBJECTIVES

The aim of the study was to investigate the effects of different loads on tremor around 10 Hz during fatiguing contractions.

METHODS

Eighteen healthy volunteers performed sustained isometric knee extensions at 30%, 50% and 70% maximum voluntary contraction (MVC). During the fatiguing contractions, mechanical recordings were made with a high-resolution force sensor. Tremor-power was calculated for the 6-20 Hz frequency window as a function of time normalized to endurance time.

RESULTS

Initial tremor power was different between the high and low load tasks. Changes of tremor with contraction time differed between the three tasks, in that tremor of the 30% MVC contraction showed the least decrease throughout the sustained contraction, whilst that of the 50% and 70% MVC showed progressively higher decreases. At failure, all 3 contractions merged to the same tremor level.

CONCLUSION

Load-dependent, fatigue-related 6-20 Hz tremor changes during sustained submaximum voluntary contractions seem mainly the consequence of recruitment of new units and fatigue-related properties of the high threshold motor units of muscles.

[Clinical gait analysis--methods, limitations and possible applications]

Human gait is a complex and cyclic movement. Gait analysis of human walking can be done either without any technical support, or in combination with complex and expensive equipment. Modern gait analysis is based on the integration of multiple components to derive a complete analysis of gait. These methods may include observation, videotaping, electromyography, kinematics, kinetics and energetics. The results gained from these methods may then be used to determine the treatment course of a subject with gait abnormalities or to document the effects of therapeutical intervention. The purpose of this article is to provide an overview of the most common used methods in gait analysis. Emphasis will be placed on the type of information that can be derived from each component and how this information can be used clinically.

Force distribution across the heel of the hand during simulated manual chest compression

According to most published guidelines of cardiopulmonary resuscitation chest compression is performed on the lower half of the sternum by compressing the sternum with the heel of one hand and the other hand on top of the first. In all guidelines and during CPR training great importance is attributed to exact localisation of the so-called compression point. In a laboratory investigation we assessed the force distribution across the heel of the hand and defined the total breadth in contact with the sternum. In order to find out whether there is any difference in the force pattern with the right or the left hand in direct contact with the sternum we determined the resultant maximal force of that part of the heel of the hand exerting the maximal force. A total of 12 anaesthetists performed simulated chest compressions onto a flat surface covered with an integrated force sensor mat. The distance between the most ulnar part and the most radial part of the hand was determined to be 9.2 cm. Similar mean total forces were measured (right hand in contact: 644 N; left hand in contact: 621 N). In all except one anaesthetist the hypothenar part of the heel exerted a significantly higher force compared to the thenar part, independent of whether the right hand or the left hand was in contact. The distance between points of maximal force when the right hand or when the left hand in contact was 2.2 cm corresponding to the breadth of one and a half fingers. To reduce the potential risk of sternal fractures by chest compressions applied too far in a cephalad direction, we recommend use of the right hand in contact if the rescuer kneels at the right side of the patient and vice versa.

Comparison of two insole materials using subjective parameters and pedobarography (pedar-system)

INTRODUCTION:: The objective of this trial was to investigate two commonly used insole materials prescribed for shock-absorption and cushioning concerning subjective and pedobarographic parameters. The design was prospective, controlled, randomized and single-blinded. MATERIAL AND METHODS:: A convenient sample of six healthy male adults without any history of leg or foot injury or pain wore -- in random order -- the custom-made insoles for one week. For both insoles the same base material (TEPEFON(R)) was used, insole 1 was covered with PLASTAZOTE(R) I, 3 mm, insole 2 with PPT, 3 mm. Both insoles had a metatarsal pad. After one week of wearing, in-shoe plantar pressures, measured at the same time of day and within the same type of indoor tennis shoes (sockliner removed), were obtained using the PEDAR-System(R) (Novel GmbH, Munich, Germany). Before each measurement the PEDAR-insoles were calibrated and the subject walked around for 5 minutes to get aquainted with the device. Three trials were performed for three different conditions and average values were determined: PEDAR-insole alone, with PLASTAZOTE(R) insole, with PPT(R) insole. Data were collected at self selected speed, gait velocity was determined using two optical switches on a 10 m walkway. Pressures were normalized to body weight. Main outcome parameters were 'Maximal Peak Pressure' (MPP) and 'Pressure Time Integral' (PTI). These parameters were determined for the whole footsole, medial and lateral heel, medial and lateral midfoot, medial, middle and lateral forefoot, hallux and toes II-V. Additionally the subjects filled in a questionnaire including: time wearing the insoles daily (in hours), sweating (visual analogue scale -- VAS), wearing comfort (VAS), perceived discomfort (location). Three months after the trial they were asked via telephone call whether they were still using the insoles. RESULTS:: 1. The overall MPP and PTI values did not differ significantly between the PEDAR-insole alone and the investigated inserts. There was a tendency for both insoles towards lower MPP and PTI values in all regions except for the toes, especially for the PPT(R) insole. 2. The questionaire showed a significantly higher wearing comfort for the PPT(R) insole in contrast to the PLASTAZOTE(R) insole, though all subjects sweated more with the PPT(R) material. Four of the six subjects experienced discomfort due to the metatarsal pad within the PLASTAZOTE(R) insole, only one within the PPT(R) insole. 3. None of the subjects continued to use the PLASTAZOTE(R) insole, but three continued to use the PPT(R) insoles. DISCUSSION:: Despite the significant differences in the subjective parameters, especially wearing comfort, no statistical significant difference for the overall MPP and PTI values between the PEDAR-insole alone and the investigated insoles or in between the insoles tested could be obtained. Yet there was a tendency for both insoles to lower MPP and PTI values in all regions except for the toes. This might be due to the thickness of the insoles and the reduced space within the toe box. The subjectively better tolerated PPT(R) insole tended to lower MPP and PTI more than the PLASTAZOTE(R) insole. CONCLUSION:: Wearing comfort and pedobarographic outcome measurements did not correlate significantly in this trial. Yet there was a tendency for the subjectively better tolerated PPT(R) insole to lower MPP and PTI more.