Hip Belt Research Articles

Determination of dynamic air gap thickness and analysis of its relationship with firefighters’ joint movement

ABSTRACT Objectives. The purpose of this study was to calculate the dynamic air gap thickness between the human body and the turnout gear. Relationships between the air gap thickness and joint range of motion (ROM) were also explored. Methods. The air gap thickness and joint ROM of 12 male firefighters walking in a control condition with no self-contained breathing apparatus (SCBA) and three varying-strapped SCBAs were measured using three-dimensional (3D) body scanning and 3D inertial motion capture. The interpolation technique was employed to predict the air gap thickness curve during walking. The dynamic air gap thickness was compared with the joint ROM to see how they relate to the location and percentage of movement restriction. Results. During the walking, the air gap fluctuated as a sine curve. Carrying SCBA reduced the air gap thickness at the trunk most (F = 11.17, p < 0.001, η 2 = 0.63), and adjusting the shoulder strap length altered the air gap distribution at the trunk. The reduced air gap at the pelvis caused an incremental restriction on pelvis rotation. Conclusions. A compatibility design of the shoulder strap and hip belt in SCBA with the turnout jacket is suggested.

Coupled effect of load weights and belt use on male shoulder pressure redistribution

Shoulder pressure redistribution is jointly affected by backpack loads and belt support. However, the combined effect of both factors has rarely been fully evaluated. Here, we studied the coupled effect of backpack loads and belt support on shoulder pressure redistribution. All twenty-eight healthy male subjects underwent eight loading conditions with both chest and hip belts fastened (CH) and unfastened (CON) in four conditions where the backpack weighed 7.5, 15, 22.5, and 30% of body weight (BW). Shoulder pressure distribution was quantified through a pressure-sensing vest mat. The results showed that using the hip belt and chest belt was effective in relieving the high pressure in the lateral clavicle and medial trapezius region and strengthening the load-bearing capacity of shoulder. However, the assistance in pressure relief of using belt was weakened when load increased to 30% BW. This study also showed that the belt use can be effective in improving pressure asymmetry on both sides.

Concentric and eccentric hip musculotendon work depends on backpack loads and walking slopes

Hip muscle weakness is associated with low back and leg injuries. In addition, hiking with heavy loads is linked to high incidence of overuse injuries. Walking with heavy loads on slopes alters hip biomechanics compared to unloaded walking, but individual muscle mechanical work in these challenging conditions is unknown. Using movement simulations, we quantified hip muscle concentric and eccentric work during walking on 0° and ±10° slopes with, and without 40% bodyweight added loads, and with and without a hip belt. For gluteus maximus, psoas, iliacus, gluteus medius, and biceps femoris long head, both concentric and eccentric work were greatest during uphill walking. For rectus femoris and semimembranosus, concentric work was greatest during uphill and eccentric work was greatest during downhill walking. Loaded walking had greater concentric and eccentric work from rectus femoris, biceps femoris long head, and gluteus maximus. Psoas concentric work was greatest while carrying loads regardless of hip belt usage, but eccentric work was only greater than unloaded walking when using a hip belt. Loaded and uphill walking had high concentric work from gluteus maximus, and high eccentric work from gluteus medius and biceps femoris long head. Carrying heavy loads uphill may lead to excessive hip muscle fatigue and heightened injury risk. Effects of the greater eccentric work from hip flexors when wearing a hip belt on lumbar spine forces and pelvic stability should be investigated. Military and other occupational groups who carry heavy backpacks with hip belts should maintain eccentric strength of hip flexors and hamstrings.

Impact of Backpacks on Ergonomics: Biomechanical and Physiological Effects: A Narrative Review.

(1) Background: the effects of load carriage packs on human gait biomechanics, physiology and metabolism depend on the weight carried, the design of the pack and its interaction with the user. (2) Methods: An extensive search in the PubMed database was performed to find all the relevant articles using the following keywords: backpack, rucksack, backpack ergonomy and sports backpack; 60 articles were included. (3) Results and significance: Double pack (DP) and T-pack (TP) designs are recommended solutions for school children, compared with backpacks (BP). For soldiers and hikers, a backpack remains the best compromise. A hip belt is recommended for BPs as well as for the back of DPs. Shorter and stiffer shoulder straps combined with a higher and tighter load placement on the back provide the best combination in terms of balance, muscle activation and energy expenditure. It is, therefore, possible to determine guidelines for designing the optimal load carriage system, depending on the application. (4) Conclusions: based on the available evidence, DP and TP are advantageous in terms of posture. DP is better than conventional BPs in terms of balance and muscle activation, but has the disadvantage of limited visibility, thermal sensation and obstructed ventilation. In general, it is desirable not to exceed 40% of body mass (BM).

Systemy umożliwiające identyfikację upadku z wysokości

The article discusses two types of systems developed at CIOP-PIB, which enable the identification of human falls from a height. The operation of the first system is based on an accelerometric measuring system implemented in the hip belt, which is an element of the equipment protecting against falls from a height. The operation of the second system is based on the analysis of the recorded video. The methods and results of calibration and verification tests of both designed systems, which were used for the preliminary tests, were presented. During these tests, the participant performed specific exercises: sitting down and simulating falling. The comparison of the test results showed a high convergence between the values measured with the acceleration sensors and the values obtained on the basis of the image analysis. The described systems can therefore be used for fall dentification and as initiators of devices for dynamic shortening of the fall path, which will reduce the forces acting on a person during restraining his fall from a height.

A backpack load sharing model to evaluate lumbar and hip joint contact forces during shoulder borne and hip belt assisted load carriage

Musculoskeletal injuries of the lumbar spine occur frequently among military service members and are associated with heavy backpack loads. Musculoskeletal modeling and simulation facilitate biomechanical evaluation to compare different backpack designs. We developed a backpack attachment model that can be tuned to represent various load distributions between the torso and pelvis. We generated walking simulations to estimate muscle and joint contact forces of unloaded walking and while carrying 38 kg using shoulder-borne backpacks and hip belt-assisted backpacks for six U.S. Marines. Three-dimensional peak and average lumbar (L4-L5) and hip joint contact forces over the stance phase were compared between each load condition. Axial L4-L5 and axial and anterior hip joint contact forces were greater during both backpack conditions compared to the unloaded condition. Joint contact forces were similar between backpack conditions. Future studies incorporating additional participants, walking conditions, and backpack load distributions are suggested for further model development and backpack design evaluation.

Comparison of muscle activation of 3 different hip belt squat techniques

The purpose of this study was to differentiate between muscular activity of three different types of belt squats (SquatMax-MD, Pit Shark and Monster Rhino) and the muscle activation of the rectus femoris, vastus medialis oblique, gluteus maximus, and gluteus medius.

Seating and positioning system in wheelchairs of people with disabilities: a retrospective study

Objective To characterize and quantify the seating and positioning items in wheelchairs prescribed and dispensed from 2005–2018 in relation to the necessities of the diagnoses served. Methods A convenience cross-sectional sample survey was used in the setting of an occupational therapy service from a specialized orthopaedic hospital. Records of people with disabilities who use a wheelchair (n = 1730) were surveyed for the following data: sociodemographic information (gender and age), diagnosis, whether a new wheelchair was received, whether wheelchair seating and positioning system were received, and the prescribed items. Results Of the 1730 users, 73.7% received a new wheelchair and 26.3% already had one donated by other services and/or purchased by the patient. Almost all the wheelchairs needed seating and positioning system in their structure (82.3%), and only 307 wheelchairs (17.7%) did not require any. The most frequent item was the hip belt (82.3%), followed by the removable solid wooden seat, and removable solid wooden backrest (81.3 and 80.9%, respectively). Conclusions It is noted that the sample studied required many seating and positioning items for their wheelchairs. Despite the high demand for these assistive technological resources, research in this area is scarce. Little is known about which seating and positioning system is ideal for each user profile, which makes it difficult to organize the services that act in the provision of such equipment and the professional practice based on evidence. Implications for Rehabilitation Seating and positioning system in wheelchair provide the user with the postural control necessary for daily activities, the maintenance of independence, and interaction with the environment. Indicating the best seating and positioning system is one of the most challenging tasks for healthcare professionals specializing in its prescription because it can be difficult to assess which components best meet the needs of an individual. The research proposed by this study has produced important evidences for the clinical practice of professionals that act on the prescription of wheelchairs and seating and positioning items for people with disabilities, presenting data that contribute to a better indication of these equipment’s.

Early adulthood onset of muscle weakness in facioscapulohumeral muscular dystrophy and physical therapy management: An unusual case report

Facioscapulohumeral muscular dystrophy is an uncommon and rarely seen progressive myopathic disorder. It is usually seen during periods of rapid growth (4-5 years). Proximal and distal upper extremities characteristically show weakness and atrophy. Face, scapular, shoulder, leg, hip belt muscles are frequently asymmetrically affected. In this paper, a case is presented of this rare, difficult to diagnose disease, not previously reported in this age group, and the findings are discussed in the light of information of earlier cases in Turkey. A 26-year old female patient presented at Hacettepe University Neurology outpatient clinic with complaints of muscle weakness and atrophy in the left arm and leg, which had been ongoing for 4 years. The muscle weakness of left upper, lower extremities and right limb, further cervical cord atrophy, winging scapulae, abnormal spinal curvature were observed. This case report presents information about the differential diagnosis, detailed symptoms, and physical therapy management of a Fascioscapulohumeral patient.

Influence of inertial resistance squat exercise protocol based on novel exercise intensity determination on physical fitness of older adult women

&amp;lt;p&amp;gt;The aim of the study was to examine practical implications and actual effects of the 8-week progressive resistance exercise protocol with the custom-made inertial device on sit-to-stand, 6- MWT, functional reach, up-and-go test results and Rate of Perceived exertion (RPE) among older adult women (age 65-74). Thirty-seven healthy volunteers were randomly assigned to the control group (n = 11) and to two exercise &amp;amp;ndash; inertial (n = 12) and traditional (n = 14) &amp;amp;ndash; groups. The participants performed hip belt squats on the inertial device and kettlebell squats, respectively. Exercise intensity was relatively adjusted using mass moment of inertia (MMI) of the cylindrical weight and %1RM. Time under tension was equalized between groups by the type of the exercise executed. Tests were performed before and after the intervention. Moreover, RPE was monitored after each exercise set. We used two-way repeated measures ANOVA to assess exercise-related differences in test results and to assess intensityrelated differences in RPE. The Senior Fitness Test results significantly differed in pre and post measurements, regardless of the group. A significant time x group interaction was only found in Sit-to-stand test results. RPE results significantly varied from each other across intensities. Statistically different results among groups were only found at the highest intensity (70%). The results indicate that inertial resistance exercise using the novel exercise intensity determination on the inertial device is a useful and less strenuous alternative to traditional resistance exercise among older adult women while performing squats.&amp;lt;/p&amp;gt;

The Influence of Backpack Weight and Hip Belt Tension on Movement and Loading in the Pelvis and Lower Limbs during Walking.

The introduction of hip belts to backpacks has caused a shift of loading from the spine to the hips with reported improvements in musculoskeletal comfort. Yet the effects of different hip belt tensions on gait biomechanics remain largely unknown. The goal of this study was to assess the influence of backpack weight and hip belt tension on gait biomechanics. Data from optical motion capture and ground reaction forces (GRF) during walking were acquired in nine healthy male subjects (age 28.0 ± 3.9 years). Six configurations of a commercial backpack were analyzed, that is, 15 kg, 20 kg, and 25 kg loading with 30 N and 120 N hip belt tension. Joint ranges of motion (ROM), peak GRF, and joint moments during gait were analyzed for significant differences by repeated measures of ANOVA with Bonferroni post hoc comparison. Increased loading led to a significant reduction of knee flexion-extension ROM as well as pelvis rotational ROM. No statistically significant effect of hip belt tension magnitudes on gait dynamics was found at any backpack weight, yet there was a trend of increased pelvis ROM in the transverse plane with higher hip belt tension at 25 kg loading. Further research is needed to elucidate the optimum hip belt tension magnitudes for different loading weights to reduce the risks of injury especially with higher loading.

Mitigating load carriage burden – The Dynamic Weight Distribution (DWD) hip belt

Mitigating load carriage burden – The Dynamic Weight Distribution (DWD) hip belt

The energetic consequences of wearing a belt-supported armored vest during overground hiking

Purpose: Load carriage for military ground troops on patrol can include a rifle, operational kit, a loaded backpack, and an armored vest, such as the modular tactical vest (MTV) used in this study. As the total mass of transport increases, so too does the potential for fatigue and injuries. Thus, finding the most economical and comfortable load carriage system may allow troops to perform their duties in the safest and most effective manner. The purpose of this study was to assess the energetic and cardiovascular effects of using an MTV with a backpack-style hip belt during overground hiking. It was hypothesized that both energetic and cardiovascular demands of overground hiking with an MTV would improve with the use of the hip belt.

Integrating a hip belt with body armour reduces the magnitude and changes the location of shoulder pressure and perceived discomfort in soldiers

Soldiers carry heavy loads that may cause general discomfort, shoulder pain and injury. This study assessed if new body armour designs that incorporated a hip belt reduced shoulder pressures and improved comfort. Twenty-one Australian soldiers completed treadmill walking trials wearing six different body armours with two different loads (15 and 30 kg). Contact pressures applied to the shoulders were measured using pressure pads, and qualitative assessment of comfort and usability were acquired from questionnaires administered after walking trials. Walking with hip belt compared to no hip belt armour resulted in decreased mean and maximum shoulder pressures (p < 0.005), and 30% fewer participants experiencing shoulder discomfort (p < 0.005) in best designs, although hip discomfort did increase. Laterally concentrated shoulder pressures were associated with 1.34-times greater likelihood of discomfort (p = 0.026). Results indicate body armour and backpack designs should integrate a hip belt and distribute load closer to shoulder midline to reduce load carriage discomfort and, potentially, injury risk.Practitioner Summary: Soldiers carry heavy loads that increase their risk of discomfort and injury. New body armour designs are thought to ease this burden by transferring the load to the hips. This study demonstrated that designs incorporating a hip belt reduced shoulder pressure and shoulder discomfort compared to the current armour design.

Validation of an instrumented dummy to assess mechanical aspects of discomfort during load carriage.

Due to the increasing load in backpacks and other load carriage systems over the last decades, load carriage system designs have to be adapted accordingly to minimize discomfort and to reduce the risk of injury. As subject studies are labor-intensive and include further challenges such as intra-subject and inter-subject variability, we aimed to validate an instrumented dummy as an objective laboratory tool to assess the mechanical aspects of discomfort. The validation of the instrumented dummy was conducted by comparison with a recent subject study. The mechanical parameters that characterize the static and dynamic interaction between backpack and body during different backpack settings were compared. The second aim was to investigate whether high predictive power (coefficient of determination R2>0.5) in assessing the discomfort of load carriage systems could be reached using the instrumented dummy. Measurements were conducted under static conditions, simulating upright standing, and dynamic conditions, simulating level walking. Twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt, were assessed. The mechanical parameters were measured in the shoulder and the hip region of the dummy and consisted of average pressure, peak pressure, strap force and relative motion between the system and the body. The twelve configurations consisted of three different weights (15kg, 20kg, and 25kg), combined with four different hip belt tensions (30N, 60N, 90N, and 120N). Through the significant (p<0.05) correlation of the mechanical parameters measured on the dummy with the corresponding values of the subject study, the dummy was validated for all static measurements and for dynamic measurements in the hip region to accurately simulate the interaction between the human body and the load carriage system. Multiple linear regressions with the mechanical parameters measured on the dummy as independent variables and the corresponding subjective discomfort scores from the subject study as the dependent variable revealed a high predictive power of the instrumented dummy. The dummy can explain 75% or more of the variance in discomfort using average pressures as predictors and even 79% or more of the variance in discomfort using strap forces as predictors. Use of the dummy enables objective, fast, and iterative assessments of load carriage systems and therefore reduces the need for labor-intensive subject studies in order to decrease the mechanical aspects of discomfort during load carriage.

The Effect of Backpack Carriage on the Biomechanics of Walking: A Systematic Review and Preliminary Meta-Analysis.

The aim of this systematic review was to evaluate the impact of bilaterally symmetrical backpack systems borne on the posterior trunk on walking biomechanics, as backpacks represent the most prevalent method of load carriage in the military and civilian population. A search of electronic databases was performed for studies that only investigated posteriorly-borne backpack carriage during level-grade walking (treadmill and over ground). Methodology of studies was assessed, and both meta-analysis and qualitative synthesis were completed. Fifty-four studies were included in this review. In summary, the available literature showed that backpack carriage in walking was associated with an increased trunk flexion angle, increased hip and ankle range of motion, increased vertical and horizontal ground reaction force, increased cadence, and reduced stride length. Several variations in backpack carriage protocols could explain between-study variations in results, including: walking speed, backpack carriage skill level, the use of a hip belt, and posterior displacement of the load away from the trunk. The findings of this systematic review will inform backpack carriage practices in the area of injury risk assessment and physical performance enhancement.

Patient assistive system for the shoulder joint

Abstract The mobility of the upper extremity is essential for everyday activities and for independent living. Shoulder disorders affect the range of motion, therefore a patient assistive system (PAS) for the shoulder joint can be used to compensate the restrictions. The developed PAS supports up to 120° of flexion and abduction. The portable dynamic orthotic consists of two levers and is attached to a hip belt. The upper arm of the patient is connected to the device using a brace. The prototype is driven by one motor and controlled by surface electromyography (EMG). The functionality of the system was successfully verified by tests with healthy subjects. For further development, a study with shoulder patients will be performed and health professionals will evaluate the PAS.

Load Carriage-Related Paresthesias: Part 1: Rucksack Palsy and Digitalgia Paresthetica.

This is the first of a two-part article discussing loadcarriage- related paresthesias, including brachial plexus lesions (rucksack palsy), digitalgia paresthetica, and meralgia paresthetica. Paresthesias are sensations of numbness, burning, and/or tingling, usually experienced as a result of nerve injury, compression, traction, or irritation. Rucksack palsy is a traction or compression injury to the brachial plexus, caused by the shoulder straps of the rucksack. The patient presents with paresthesia, paralysis, cramping with pain, and muscle weakness of the upper limb. Muscle-strength losses appear to be greater in those carrying heavier loads. Hypothetical risk factors for rucksack palsy include improper load distribution, longer carriage distances, and load weight. Nerve traction, compression, and symptoms may be reduced by use of a rucksack hip belt; wider, better-padded, and proper adjustment of the shoulder straps; reduction of weight in the rucksack; a more symmetric distribution of the load; and resistance training to improve the strength and hypertrophy of the shoulder muscles. Assessment and neck joint and nerve mobilization may relieve brachial plexus tension and reduce symptoms. Another load-carriage-related disorder is digitalgia paresthetica, likely caused by compression of the sensory digital nerves in the foot during load carriage. Patients have paresthesia in the toes. Although no studies have demonstrated effective prevention measures for digitalgia paresthetica, reducing loads and march distances may help by decreasing the forces and repetitive stress on the foot and lower leg. Specialty evaluations by a physical therapist, podiatrist, or other healthcare provider are important to rule out entrapment neuropathies such as tarsal tunnel syndrome. Part 2 of this article will discuss meralgia paresthetica.

Comparison of muscle activation of hip belt squat and barbell back squat techniques

BACKGROUND: Hip belt squats are believed to have been introduced in 1970. By removing the load from the shoulders and upper trapezius, the hip belt squat places emphasis on the legs with less load on the spine. No peer-reviewed research exists on the muscle recruitment patterns of a hip belt squat, or how it compares in muscle activation to other squatting activities. OBJECTIVE: The purpose of the study was to determine lower extremity muscle activation in a hip belt squat (SquatMax = MD) in comparison with a barbell back squat. METHODS: Thirteen participants performed four repetitions of an 8-RM squat using three different techniques: hip belt squat without a band, hip belt squat with a band, and barbell back squat. Electromyographic data were collected from six muscles: quadriceps, biceps femoris, hip adductors, hip abductors, gluteus maximus, and gastrocnemius. RESULTS: ANOVA revealed no significant difference in muscle activity between devices. The only muscle group statistically different between genders was the gastrocnemius (p = 0.04). Hip adductor activity was lowest and hip abductor activity was highest when performing a hip belt squat with the band for both genders. Likewise, the adductor to hamstring ratio was lowest with the hip belt squat. CONCLUSIONS: Given the lack of significant difference in the muscle activity between the squat techniques, one needs to look at other attributes to determine both the scientific and, consequently, the practical value. Given the placement of the belt around the pelvis, one positive attribute for the hip belt squat is the ability to unload the shoulders and spine. Another positive attribute for the hip belt squat is the higher hip abductor to adductor ratio. This could be very important for injury prevention and patella tracking. While the back squat has slightly higher hamstring recruitment, which is important in ACL injury prevention, the hip belt squat may address this by offsetting the free weight with the use of an additional band. If a free weight hip belt squat device is available, it may be a better alternative to the traditional barbell squat technique.

Second Spine: Upper Body Assistive Device for Human Load Carriage

This study presents the development of second spine, an upper body assistive device for human load carriage. The motivation comes from reducing musculoskeletal injuries caused by carrying a heavy load on the upper body. Our aim was to design a wearable upper body device that can prevent musculoskeletal injuries during human load carriage by providing a secondary load pathway—second spine—to transfer the loads from shoulders to pelvis while also allowing a good range of torso motion to the wearer. Static analysis of the backpack and the second spine was first performed to investigate the feasibility of our concept design. The development of second spine had two considerations: load distribution between shoulders and pelvis, and preserving the range of torso motion. The design was realized using load bearing columns between the shoulder support and hip belt, comprising multiple segments interconnected by cone-shaped joints. The performance of second spine was evaluated through experimental study, and its biomechanical effects on human loaded walking were also assessed. Based on the findings from second spine evaluation, we proposed the design of a motorized second spine which aims to compensate the inertia force of a backpack induced by human walking through active load modulation. This was achieved by real-time sensing of human motion and actuating the motors in a way that the backpack motion is kept nearly inertially fixed. Simulation study was carried out to determine the proper actuation of motors in response to the human walking kinematics. The performance of motorized second spine was evaluated through an instrumented test-bed using Instron machine. Results showed a good agreement with simulation. It was shown that the backpack motion can be made nearly stationary with respect to the ground which can further enhance the effectiveness of the device in assisting human load carriage.