Lumbopelvic rhythm in the sagittal plane: A review of the effects of participants and task characteristics

Lumbo-Pelvic Rhythm Monitoring Using Wearable Technology with Sensory Biofeedback: A Systematic Review

As an essential lower-back movement pattern, lumbo-pelvic rhythm (LPR) during forward trunk flexion and backward return has been investigated on a large scale. It has been suggested that abnormalities in lumbo-pelvic coordination are related to the risk of developing low back disorders. However, considerable differences in the approaches used to monitor LPR make it challenging to integrate findings from those investigations for future research. Therefore, the aim of this systematic review was to summarize the use of wearable technology for kinematic measurement with sensory biofeedback for LPR monitoring by assessing these technologies' specific capabilities and biofeedback capacities and exploring their practical viability based on sensor outcomes. The review was developed following the PRISMA guidelines, and the risk of bias was analyzed using the PREDro and STROBE scales. PubMed, Web of Science, Scopus, and IEEEXPLORE databases were searched for relevant studies, initially returning a total of 528 articles. Finally, we included eight articles featuring wearable devices with audio or vibration biofeedback. Differences in protocols and limitations were also observed. This novel study presents a review of wearable tracking devices for LPR motion-mediated biofeedback for the purpose of correcting lower back posture. More research is needed to determine the long-term effectiveness of these devices, as well as their most appropriate corresponding methodologies.

Acute and Chronic Effects of Supervised Flexibility Training in Older Adults: A Comparison of Two Different Conditioning Programs

Flexibility training is a fundamental biological process that improves the quality of life of the elderly by improving the ranges of motion of joints, postural balance and locomotion, and thus reducing the risk of falling. Two different training programs were assessed acutely and after 12 weeks by means of the sit-and-reach test. Thirty-one healthy older adults were randomly divided into three groups: the Experiment I group (Exp) performed strength and static stretching exercises; the Experiment II group performed dynamic and static stretching exercises; and participants assigned to the control group maintained a sedentary lifestyle for the entire period of the study. Flexibility acutely increased in Exp I by the first (ΔT0 = 7.63 ± 1.26%; ES = 0.36; p = 0.002) and second testing sessions (ΔT1 = 3.74 ± 0.91%; ES = 0.20; p = 0.002). Similarly, it increased in Exp II significantly by the first (ΔT0 = 14.21 ± 3.42%; ES = 0.20; p = 0.011) and second testing sessions (ΔT1 = 9.63 ± 4.29%; ES = 0.13; p = 0.005). Flexibility significantly increased over the 12 weeks of training in Exp I (ΔT0 - T1 = 9.03 ± 3.14%; ES = 0.41; p = 0.020) and Exp II (ΔT0 - T1 = 22.96 ± 9.87%; ES = 0.35; p = 0.005). The acute and chronic differences between the two groups were not significant (p > 0.05). These results suggest the effectiveness of different exercise typologies in improving the flexibility of the posterior muscular chains in older adults. Therefore, the selection of a program to optimize training interventions could be based on the physical characteristics of the participants.

Relationship between pelvic floor muscle function and changes in lumbar spine and hip motion due to pelvic floor muscle contraction

BACKGROUND

Pelvic floor muscles (PFM) are important for lumbar stability. However, the relationship between lumbar and hip motion angle changes (MAC) caused by PFM contraction and each PFM's function remains unclear.

OBJECTIVE

To clarify the lumbar spine and hip motion changes produced by PFM contraction and the relationship between MAC and PFM function.

METHODS

In 21 healthy females, motion angle was measured for prone hip extension movement using natural movement (NM), PFM contracting movement (PM), and reducing lumbar movement (RM) methods. The PFM functional indices were bladder base elevation distance, continuous bladder base elevation time, and pelvic floor location.

RESULTS

The PM showed no significant difference in lumbar motion angle but had significantly smaller hip motion than the NM (NM; 26.1 ± 8.3, PM; 29.2 ± 11.0). MAC was significantly greater in RM (lumbar spine; 4.4 ± 3.2, hip; 5.9 ± 8.7) than in PM (lumbar spine; 0.4 ± 4.4, hip; 3.1 ± 5.1) for both the lumbar spine and hip. Lumbar spine and hip MAC of PM was significantly correlated with pelvic floor location (lumbar spine; r=-0.44, hip; r= 0.54).

CONCLUSION

PFM contraction does not attenuate lumbar spine motion but reduces hip motion. MAC due to PFM contraction during lumbar movement tasks is related to the PFM functional index.

Relationship between lumbar spine motor control ability and perceptual awareness during prone hip extension movement in people with low back pain

PURPOSE

The purpose of this study was to clarify the differences in lumbar spine and hip joint motor control ability (MCA) in prone hip extension (PHE) between individuals with and without low back pain (LBP). It also aimed to determine the relationship between lumbar spine and hip joint MCA and lumbar perceptual awareness in individuals with LBP.

METHODS

In total, 78 university students (20 with LBP and 58 without) were included in the study. The MCA of the lumbar spine and hip joint in PHE and perceptual awareness were evaluated. The MCA of the lumbar spine and hip joint was measured using a wearable sensor. Subsequently, a comparison of the MCA of the lumbar spine and hip joints of the participants and the relationship between MCA and lumbar perceptual awareness were examined.

RESULTS

The MCA of the LBP group was higher than that of the non-LBP group in motion on the sagittal plane. In addition, perceptual awareness was negatively correlated with MCA in the sagittal plane in the lumbar spine.

CONCLUSION

People with LBP had higher lumbar spine and hip joint MCA than those without LBP. Perceptual awareness was associated with lumbar spine and hip joint MCA in people with LBP. J. Med. Invest. 69 : 38-44, February, 2022.

Relationships among lumbar hip motion angle, perceptual awareness, and low back pain in young adults

[Purpose] We aimed to examine the relationships among low back pain, lumbar-hip motion angle, and lumbar perceptual awareness in young adults to improve the treatment of low back pain. [Participants and Methods] Data were collected from 36 university students with low back pain. The items included for evaluation were the low back pain intensity (Numeric Rating Scale), disability due to low back pain (Oswestry Low Back Pain Disability Index), lumbar spine and hip motion angles in test movements, and perceptual awareness (Fremantle Back Awareness Questionnaire). The test movements employed included trunk forward bending, trunk back bending, and prone hip extension. The motion angles of the lumbar spine and hip joints were measured using a wearable sensor. [Results] The Numeric Rating Scale was not correlated with the lumbar hip motion angle and perceptual awareness. The Oswestry Low Back Pain Disability Index was correlated with lumbar hip motion angles, at the beginning of trunk forward bending and at maximum trunk backward bending, and with perceptual awareness. [Conclusion] There are relationships among disabilities due to low back pain, lumbar hip motion angles, and perceptual awareness in each test movement; however, they vary depending on the type and angle of the test movement conducted.

Relationship between iliopsoas muscle thickness and hip angle during squats in different pelvic positions

[Purpose] This study aimed to investigate the relationships among the changes in iliopsoas muscle thickness, hip angle, and lower limb joint moment during squatting in different pelvic positions to help in performing hip-dominant squatting exercises. [Participants and Methods] The participants were seven healthy adult males. The measurement task consisted of squatting with 60 degrees of knee flexion in three positions: the anterior, neutral, and posterior pelvic tilt positions. The iliopsoas muscle thickness was measured in the center of the inguinal region using ultrasonography. A three-dimensional motion analysis system was used to measure the joint angles and joint moments. [Results] There were no significant differences in pelvic angles between the pelvic positions. The hip angle differences were significantly higher in the anterior and neutral pelvic tilt positions compared to those in the posterior tilt position. Only the anterior pelvic tilt position had a significantly positive correlation with iliopsoas muscle thickness and hip angle differences. [Conclusion] Squatting in the neutral or posterior pelvic tilt position was not associated with hip angle and iliopsoas muscle thickness changes, whereas squatting in an anterior pelvic tilt position was associated with changes in the iliopsoas muscle thickness and hip flexion angle. Our findings suggest that activation of the iliopsoas muscle might be necessary to promote hip-dominant squatting.

Changes in Lumbo-Pelvic Coordination of Individuals With and Without Low Back Pain When Wearing a Hip Orthosis

Individuals with low back pain demonstrate an abnormal lumbo-pelvic coordination compared to back-healthy individuals. This abnormal coordination presents itself as a reduction in lumbar contributions and an increase in pelvic rotations during a trunk forward bending and backward return task. This study investigated the ability of a hip orthosis in correcting such an abnormal lumbo-pelvic coordination by restricting pelvic rotation and, hence increasing lumbar contributions. The effects of the hip orthosis on the lumbo-pelvic coordination were investigated in 20 low back pain patients and 20 asymptomatic controls. The orthosis reduced pelvic rotation by 12.7° and increased lumbar contributions by 11%. Contrary to our expectation, orthosis-induced changes in lumbo-pelvic coordination were smaller in patients; most likely because our relatively young patient group had smaller unrestricted pelvic rotations compared to asymptomatic individuals. Considering the observed capability of a hip orthosis in causing the expected changes in lumbo-pelvic coordination when there is a relatively large pelvic contribution to trunk motion, application of a hip orthosis may provide a promising method of correcting abnormal lumbo-pelvic coordination, particularly among patients who demonstrate larger pelvic rotation, that warrants further investigation.

Habitual posture and weekly time spent sitting do not contribute to the lumbopelvic curvature during active unilateral knee extension in sitting test

[Purpose] To investigate whether habitual pelvic posture and time spent sitting are primary contributing factors to performance in the active unilateral knee extension in sitting test in young people. [Participants and Methods] The participants’ ages ranged from 20 to 40 years. LUMOback, a wearable electronic device, was used to measure the proportion of the days spent in a neutral pelvic posture (posture score) and time spent sitting over a week. The lumbopelvic sagittal curvature from T12 to S2 (θ) during the active unilateral knee extension in sitting test was also assessed using a flexible ruler. A multiple regression analysis was performed with the primary independent variables of the posture score and time spent sitting, undertaking priori considerations of potential confounders of sex, and pain condition on the θ value. [Results] Eighty participants (21.7 ± 3.8 years) were enrolled in the study (24 males and 56 females). Neither the posture score nor time spent sitting statistically significantly contributed to the θ value. [Conclusion] Neither the proportion of the day spent with neutral pelvic posture nor time spent sitting detected by LUMOback was the primary contributing factor to the active unilateral knee extension in sitting test performance.

The immediate and prolonged effects of military body armor on the relative timing of thorax and pelvis rotations during toe-touch and two-legged squat tasks

Although military body armor is an effective life saver, it considerably loads more weight on the warfighters, increasing the risk of musculoskeletal injury. This study investigated the immediate and prolonged effects of wearing body armor on timing aspect of lumbo-pelvic coordination during the toe-touch (TT) and two-legged-squat (TLS) tests. A cross-over study design was used wherein twelve asymptomatic and gender-balanced individuals completed two experimental sessions with and without body armor. A session included two similar sets of tests, before and after exposure to a treadmill walk, containing a TT and a TLS test with ten cycles of fast bending and return. Reflective markers were attached on the participants to capture the kinematics of body segments in conjunction with a motion capture system. The mean absolute relative phase (MARP) and deviation phase (DP) between the thorax and pelvis were calculated for each test. The pre-walk MARP in the return was significantly larger with versus without body armor (p = 0.022), while there were no significant effects of body armor on the other outcome measures. In addition, the pre-walk MARP and DP in the bending and return, as well as the walk-induced changes in the MARP in the bending phase were significantly larger in TLS versus TT (p < 0.026). Therefore, using a body armor immediately made the lumbo-pelvic coordination less in-phase during return, but no prolonged effects were found. Further investigation is necessary to specify chances wearing a body armor increases the risk of musculoskeletal injuries in the lower back and lower extremities joints.

Sex-dependent differences in lumbo-pelvic coordination for different lifting tasks: A study on asymptomatic adults

During manual material lifting, the sagittal motion is mainly characterized through the lumbo-pelvic coordination, which is quantified by the ratio between the lumbar and hip rotations (L/P ratio). Alteration in the L/P ratio is an important indicator for low back pain (LBP). Previous studies demonstrated sex-dependent differences in LBP prevalence during lifting activities. However, the sex-dependent differences in the L/P ratio during different lifting tasks has to data not been investigated. An optoelectronic system was used to measure the sagittal lumbo-pelvic motion in 10 males and 10 females. Task A was lifting one weight from the ground in front of the body to three target heights with straight knees (A1-3: abdomen, chest and head levels, respectively). Task B was lifting two identical weights from the ground at the sides of the body to three target angles with bended knees (B1-3: arms close and 45° and 90° abducted to the trunk, respectively). Lifts of 10 kg (males and females) and 20 kg (males only) were performed and three phases were investigated: Phase 1 - pure flexion without load, Phase 2 - lifting up weights, Phase 3 - lowering down weights. Females generally displayed a smaller L/P ratio than males. In Phases 2 and 3, the L/P ratio was greater than in Phase 1 for Tasks A and B. The L/P ratio increased with a greater lifting height for Task B, but displayed no difference neither between lifting 10 kg and 20 kg, nor between weight lifting and lowering for both tasks. These results can provide indications for sex-specific recommendations for safer lifting activities.

A model-based approach for estimation of changes in lumbar segmental kinematics associated with alterations in trunk muscle forces

The kinematics information from imaging, if combined with optimization-based biomechanical models, may provide a unique platform for personalized assessment of trunk muscle forces (TMFs). Such a method, however, is feasible only if differences in lumbar spine kinematics due to differences in TMFs can be captured by the current imaging techniques. A finite element model of the spine within an optimization procedure was used to estimate segmental kinematics of lumbar spine associated with five different sets of TMFs. Each set of TMFs was associated with a hypothetical trunk neuromuscular strategy that optimized one aspect of lower back biomechanics. For each set of TMFs, the segmental kinematics of lumbar spine was estimated for a single static trunk flexed posture involving, respectively, 40° and 10° of thoracic and pelvic rotations. Minimum changes in the angular and translational deformations of a motion segment with alterations in TMFs ranged from 0° to 0.7° and 0 mm to 0.04 mm, respectively. Maximum changes in the angular and translational deformations of a motion segment with alterations in TMFs ranged from 2.4° to 7.6° and 0.11 mm to 0.39 mm, respectively. The differences in kinematics of lumbar segments between each combination of two sets of TMFs in 97% of cases for angular deformation and 55% of cases for translational deformation were within the reported accuracy of current imaging techniques. Therefore, it might be possible to use image-based kinematics of lumbar segments along with computational modeling for personalized assessment of TMFs.

Age-related differences in the timing aspect of lumbopelvic rhythm during trunk motion in the sagittal plane

Forward bending and backward return of the human trunk in the sagittal plane are associated with a specific lumbopelvic rhythm, which consists of magnitude and timing aspects. In this study, the age-related differences in the timing aspect of lumbopelvic rhythm were investigated using the continuous relative phase method. Specifically, the mean absolute relative phase (MARP) between the thoracic and pelvic motions as well as variation in MARP under repetitive motions, denoted by deviation phase (DP), were characterized in sixty participants between 20 and 70years old. MARP and DP were determined for trunk forward bending and backward return tasks with self-selected slow and fast paces. The MARP and DP were both smaller (p=0.003, p<0.001 respectively) in the older versus younger age participants with no gender-related difference. In fast versus slow pace task, the MARP was smaller (p<0.001) only in forward bending, whereas the DP was smaller (p<0.001) in both the forward bending and backward return. A more in-phase and more stable lumbopelvic rhythm denoted respectively by smaller MARP and DP in older versus younger individuals maybe a neuromuscular strategy to protect the lower back tissues from excessive strain, in order to reduce the risk of injury.