Effect of time on biomechanics during exercise on the functional re-adaptive exercise device.

Mechanistic studies of the Functional Re-adaptive Exercise Device (FRED) have shown it automatically recruits Lumbar Multifidus (LM) and Transversus Abdominis (TrA) - two deep-spinal muscles that are atrophied and show altered motor control in low back pain (LBP). No studies have investigated the time required to familiarise to FRED exercise, which is required to inform future FRED based clinical trial protocols. This study therefore determined the effect of time, during FRED exercise, on biomechanical outcome measures, to establish the familiarisation period, and assess for loss of technique throughout a ten minute trial. A cohort comparison study of 148 participants, 70 experiencing low back pain, had lumbopelvic kinematics, exercise frequency and movement variability measured during a 10 minute trial. Magnitude-based inference was used to assess for familiarisation, using plots of variation over time with familiarised reference ranges. The no pain group took 170 seconds, and the back pain group took 150 seconds, to familiarise. A familiarisation period of at least 170 seconds (2.8 minutes) is recommended. This justifies, and provides a familiarisation time for use of the FRED as a motor control intervention.

Associations between community-based physiotherapy for musculoskeletal injury and health related quality of life (EQ-5D): a multi-centre retrospective analysis.

BACKGROUND: Community-based musculoskeletal physiotherapy is used to improve function and health related quality of life (HRQoL). The purpose of this retrospective, multi-centre observational study was to determine the association between community-based physiotherapy management for musculoskeletal disorders and changes in HRQoL. METHODS: Four thousand one hundred twelve patients' data were included in the study. Patients were included if they received a single period of treatment for a musculoskeletal injury or disorder. Patients were only included if they were being treated for a single morbidity. Patients received standard physiotherapy appropriate to their specific disorder, which could include health education/advice, exercise therapy, manual therapy, taping, soft tissue techniques, electrotherapy and/or acupuncture. Health related quality of life was assessed using the EQ-5D index. RESULTS: EQ-5D improved by 0.203 across all patients (d = 1.10). When grouped by anatomical site of symptom, the largest increases in EQ-5D was in foot pain (0.233; d = 1.29) and lumbar pain (0.231; d = 1.13). Improvements in EQ-5D greater than the minimum clinically important difference (MCID) were seen in 68.4% of all patients. The highest proportion of patients with positive responses to treatment were in ankle pain (74.2%) and thoracic pain (73.4%). The hand (40.5%), elbow (34.7%), and hip (33.9%) showed the greatest proportion of patients that did not respond to treatment. CONCLUSIONS: Community-based musculoskeletal physiotherapy is associated with improved health related quality of life. A randomised controlled trial is needed to determine any causal relationship between community-based physiotherapy and health related quality of life improvements.

Retrospective cohort study of the South Tyneside Exercise Referral Scheme 2009-14: predictors of dropout and barriers to adherence.

Background: Exercise Referral Schemes (ERS) are a prevalent method of increasing physical activity levels. However, they suffer from participant dropout and research predicting dropout or barriers to adherence are limited. This study aimed to focus upon the effect of referral characteristics on dropout, dropout predictors and whether self-reported barriers to exercise predict dropout. Methods: ERS data from 2009 to 2014 were retrieved for analysis. Chi-squared and t-tests were used to investigate differences between referral characteristics, and logistic regression used to investigate dropout predictors. Results: Of 6894 participants, 37.8% (n = 2608) dropped out within 6 weeks and 50.03% (n = 3449) by the final 12th week. More males adhered (P < 0.001) with dropouts being significantly younger (P < 0.001). Dropout predictors were smoking (OR = 1.58, 95% CI: 1.29-1.93) or being a Tier 3 referral (OR = 1.47, 95% CI: 1.25-1.73). Increasing age (OR = 0.98, 95% CI: 0.98-0.99), drinking alcohol (OR = 0.82, 95% CI: 0.71-0.95), secondary care referrals (OR = 0.68, 95% CI: 0.52-0.90), having a lack of motivation (OR = 0.81, 95% CI: 0.69-0.95) or a lack of childcare (OR = 0.69, 95% CI: 0.50-0.95) decreased the likelihood of dropout. Conclusion: ERS dropout continues to be problematic. Smoking and having moderate-high comorbidities predicted dropout. Increasing age and patient-reported barriers of a lack of time or childcare decreased dropout risk. The reasons for dropout require further investigation.

Movement amplitude on the Functional Re-adaptive Exercise Device: deep spinal muscle activity and movement control.

PURPOSE: Lumbar multifidus (LM) and transversus abdominis (TrA) show altered motor control, and LM is atrophied, in people with low-back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) involves cyclical lower-limb movement against minimal resistance in an upright posture. It has been shown to recruit LM and TrA automatically, and may have potential as an intervention for non-specific LBP. However, no studies have yet investigated the effects of changes in FRED movement amplitude on the activity of these muscles. This study aimed to assess the effects of different FRED movement amplitudes on LM and TrA muscle thickness and movement variability, to inform an evidence-based exercise prescription. METHODS: Lumbar multifidus and TrA thickness of eight healthy male volunteers were examined using ultrasound imaging during FRED exercise, normalised to rest at four different movement amplitudes. Movement variability was also measured. Magnitude-based inferences were used to compare each amplitude. RESULTS: Exercise at all amplitudes recruited LM and TrA more than rest, with thickness increases of approximately 5 and 1 mm, respectively. Larger amplitudes also caused increased TrA thickness, LM and TrA muscle thickness variability and movement variability. The data suggests that all amplitudes are useful for recruiting LM and TrA. CONCLUSIONS: A progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, to continue to challenge the motor control system.

Reliability and Precision of Sonography of the Lumbar Multifidus and Transversus Abdominis During Dynamic Activities.

OBJECTIVES: To determine the intrarater reliability and precision of lumbar multifidus and transversus abdominis thickness measurements using freehand sonography in a range of static and dynamic conditions. METHODS: Fifteen asymptomatic participants performed a range of exercises while sonography was used to measure absolute muscle thickness and changes in muscle thickness from rest. Exercise conditions included the abdominal drawing-in maneuver, active straight leg raise, contralateral arm lift, both unloaded and loaded, treadmill walking, and using the Functional Readaptive Exercise Device. Intraday and interday reliability was assessed by intraclass correlation coefficients, and the standard error of measurement was used to assess measurement precision. RESULTS: Good to excellent reliability was achieved for absolute transversus abdominis and lumbar multifidus thickness in all conditions. Measurement precision for absolute lumbar multifidus thickness was ≤2.8 mm for the unloaded contralateral arm lift, ≤1.8 mm for the loaded contralateral arm lift, ≤3.1 mm for treadmill walking, and ≤3.8 mm for the Functional Readaptive Exercise Device; for absolute transversus abdominis thickness, precision was ≤0.6 mm for the abdominal drawing-in maneuver, ≤0.5 mm for the active straight leg raise, ≤0.7 mm for treadmill walking, and ≤0.5 mm for the Functional Readaptive Exercise Device. Good to excellent reliability was achieved for relative transversus abdominis and lumbar multifidus thickness in all conditions. Measurement precision for relative lumbar multifidus thickness was ≤3.7% for the unloaded contralateral arm lift, ≤3.8% for the loaded contralateral arm lift, ≤6.3% for treadmill walking, and ≤7.6% for the Functional Readaptive Exercise Device; for relative transversus abdominis thickness, precision was ≤13.6% for the abdominal drawing-in maneuver, ≤6.9% for the active straight leg raise, ≤11.1% for treadmill walking, and ≤7.2% for the Functional Readaptive Exercise Device. CONCLUSIONS: Acceptable reliability and precision of measurement is achieved for absolute and relative measures of deep spinal muscle thickness using freehand sonography in relatively static and dynamic exercises.

An evaluation of the effectiveness of medial patellofemoral ligament reconstruction using an anatomical tunnel site.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability has gained popularity, and anatomical and biomechanical studies have recently altered our operative techniques. The aim of this study was to report the clinical outcome of this new anatomical MPFL reconstructive technique and investigate whether correlating factors could be identified. METHODS: Between 2009 and 2012, a total of 31 consecutive patients underwent MPFL reconstruction using an autologous gracilis graft and anatomical tunnel placement. Pre- and post-operative data were collected as a part of routine clinical practice. The preoperative assessment included a rotational profile CT scan of the lower extremity according to the Lyon protocol with TT-TG distance measurement. Outcomes were evaluated with the Kujala and Norwich patella instability (NPI) scores preoperatively and at follow-up (1.5-5.1 years). RESULTS: A significant improvement in both the Kujala (p < 0.001) and NPI (p = 0.012) scores was recorded. A medium and large negative correlations were found between TT-TG distance and Kujala score improvement (ρ = -0.48, p = 0.020) and NPI score improvement (ρ = -0.83, p = 0.042), respectively. Multiple regression analysis identified TT-TG distance, Beighton score and BMI as factors explaining the variance of Kujala score improvement. CONCLUSION: Anatomical MPFL reconstruction with the gracilis autograft for patellar instability resulted in good outcome. This underlines the importance of anatomical tunnel placement in MPFL reconstruction. With a precise preoperative work-up, factors can be identified that may guide selecting the optimal operative strategy and improve counselling of the patient. LEVEL OF EVIDENCE: Case series, Level IV.

Effects of 1 week of unilateral ankle immobilization on plantar-flexor strength, balance, and walking speed: a pilot study in asymptomatic volunteers.

CONTEXT: Ankle immobilization is often used after ankle injury. OBJECTIVE: To determine the influence of 1 week's unilateral ankle immobilization on plantar-flexor strength, balance, and walking gait in asymptomatic volunteers. DESIGN: Repeated-measures laboratory study. SETTING: University laboratory. PARTICIPANTS: 6 physically active male participants with no recent history of lower-limb injury. INTERVENTIONS: Participants completed a 1-wk period of ankle immobilization achieved through wearing a below-knee ankle cast. Before the cast was applied, as well as immediately, 24 h, and 48 h after cast removal, their plantar-flexor strength was assessed isokinetically, and they completed a single-leg balance task as a measure of proprioceptive function. An analysis of their walking gait was also completed Main Outcome Measures: Peak plantar-flexor torque and balance were used to determine any effect on muscle strength and proprioception after cast removal. Ranges of motion (3D) of the ankle, knee, and hip, as well as walking speed, were used to assess any influence on walking gait. RESULTS: After cast removal, plantar-flexor strength was reduced for the majority of participants (P = .063, CI = -33.98 to 1.31) and balance performance was reduced in the immobilized limb (P < .05, CI = 0.84-5.16). Both strength and balance were not significantly different from baseline levels by 48 h. Walking speed was not significantly different immediately after cast removal but increased progressively above baseline walking speed over the following 48 h. Joint ranges of motion were not significantly different at any time point. CONCLUSIONS: The reduction in strength and balance after such a short period of immobilization suggested compromised central and peripheral neural mechanisms. This suggestion appeared consistent with the delayed increase in walking speed that could occur as a result of the excitability of the neural pathways increasing toward baseline levels.

Post space mission lumbo-pelvic neuromuscular reconditioning: a European perspective.

Long-duration exposure to the space environment causes physical adaptations that are deleterious to optimal functioning on Earth. Post-mission rehabilitation traditionally concentrates on regaining general muscle strength, neuromuscular control, and lumbo-pelvic stability. A particular problem is muscle imbalance caused by the hypertrophy of the flexor and atrophy of the extensor and local lumbo-pelvic muscles, increasing the risk of post-mission injury. A method currently used in European human spaceflight to aid post-mission recovery involves a motor control approach, focusing initially on teaching voluntary contraction of specific lumbo-pelvic muscles and optimizing spinal position, progressing to functional retraining in weight bearing positions. An alternative approach would be to use a Functional Readaptive Exercise Device to appropriately recruit this musculature, thus complementing current rehabilitation programs. Advances in post-mission recovery of this nature may both improve astronaut healthcare and aid terrestrial healthcare through more effective treatment of low back pain and accelerated post bed rest rehabilitation.

Male body movements as possible cues to physical strength: a biomechanical analysis.

OBJECTIVES: Comparative research suggests that male courtship displays signal condition-dependent traits tofemales; these displays might also provide cues to potential male competitors. Although some associations betweenhuman movements and physical/behavioral qualities have been found, such research has typically only been conducted from a perspective of female mate choice. Here, using advanced motion capture and biomechanical analyses, we examine the extent to which male dancing provides cues about the dancer's physical qualities to both males and females. METHODS: Thirty men aged 19-37 were recorded using motion-capture technology as they danced to a standard rhythm. Participants also completed a vascular fitness test, assessments of upper- and lower-body strength, and biomechanical indices were extracted from their dance movements. Dance clips were converted into virtual humanoid characters (avatars) and rated by 27 women and 21 men on perceived dance quality. RESULTS: General linear mixed modeling revealed that both handgrip strength and arm movements of the dancer were statistically significant predictors of dance quality ratings; stronger males who displayed larger, more variable, and faster movements of their arms being rated as better dancers. There was no effect of the sex of the observer in predicting dance quality ratings, indicating that male and female observers rated dance quality equivalently. Physical fitness was not associated with perceived dance quality. CONCLUSIONS: Men and women are able to derive certain quality cues from observing male dance movements in the form of controlled stimuli. Thus, male dancing may form a condition-dependent ornament of certain aspects of mate quality.

Gait and Neuromuscular Changes Are Evident in Some Masters Club Level Runners 24-h After Interval Training Run.

Purpose: To examine the time course of recovery for gait and neuromuscular function immediately after and 24-h post interval training. In addition, this study compared the impact of different statistical approaches on detecting changes. Methods: Twenty (10F, 10M) healthy, recreational club runners performed a high-intensity interval training (HIIT) session consisting of six repetitions of 800 m. A 6-min medium intensity run was performed pre, post, and 24-h post HIIT to assess hip and knee kinematics and coordination variability. Voluntary activation and twitch force of the quadriceps, along with maximum isometric force were examined pre, post, and 24-h post significance HIIT. The time course of changes were examined using two different statistical approaches: traditional null hypothesis significance tests and "real" changes using minimum detectable change. Results: Immediately following the run, there were significant (P < 0.05) increases in the hip frontal kinematics and coordination variability. The runners also experienced a loss of muscular strength and neuromuscular function immediately post HIIT (P < 0.05). Individual assessment, however, showed that not all runners experienced fatigue effects immediately post HIIT. Null hypothesis significance testing revealed a lack of recovery in hip frontal kinematics, coordination variability, muscle strength, and neuromuscular function at 24-h post, however, the use of minimum detectable change suggested that most runners had recovered. Conclusion: High intensity interval training resulted in altered running kinematics along with central and peripheral decrements in neuromuscular function. Most runners had recovered within 24-h, although a minority still exhibited signs of fatigue. The runners that were not able to recover prior to their run at 24-h were identified to be at an increased risk of running-related injury.

Skeletal muscle deconditioning during partial weight-bearing in rodents - A systematic review and meta-analysis.

Space agencies are planning to send humans back to the Lunar surface, in preparation for crewed exploration of Mars. However, the effect of hypogravity on human skeletal muscle is largely unknown. A recently established rodent partial weight-bearing model has been employed to mimic various levels of hypogravity loading and may provide valuable insights to better understanding how human muscle might respond to this environment. The aim of this study was to perform a systematic review regarding the effects of partial weight-bearing on the morphology and function of rodent skeletal muscle. Five online databases were searched with the following inclusion criteria: population (rodents), intervention (partial weight-bearing for ≥1 week), control (full weight-bearing), outcome(s) (skeletal muscle morphology/function), and study design (animal intervention). Of the 2,993 studies identified, eight were included. Partial weight-bearing at 20%, 40%, and 70% of full loading caused rapid deconditioning of skeletal muscle morphology and function within the first one to two weeks of exposure. Calf circumference, hindlimb wet muscle mass, myofiber cross-sectional area, front/rear paw grip force, and nerve-stimulated plantarflexion force were reduced typically by medium to very large effects. Higher levels of partial weight-bearing often attenuated deconditioning but failed to entirely prevent it. Species and sex mediated the deconditioning response. Risk of bias was low/unclear for most studies. These findings suggest that there is insufficient stimulus to mitigate muscular deconditioning in hypogravity settings highlighting the need to develop countermeasures for maintaining astronaut/cosmonaut muscular health on the Moon and Mars.

Bone deconditioning during partial weight-bearing in rodents - A systematic review and meta-analysis.

Space agencies are preparing to send humans to the Moon (16% Earth's gravity) and Mars (38% Earth's gravity), however, there is limited evidence regarding the effects of hypogravity on the skeletal system. A novel rodent partial weight-bearing (PWB) model may provide insight into how human bone responds to hypogravity. The aim of this study was to perform a systematic review investigating the effect of PWB on the structure and function of rodent bone. Five online databases were searched with the following inclusion criteria: population (rodents), intervention (PWB for ≥1-week), control (full weight-bearing), outcomes (bone structure/function), and study design (animal intervention). Of the 2,993 studies identified, eight were included. The main findings were that partial weight-bearing exposure for 21-28 days at 20%, 40%, and 70% of full loading causes: (1) loss of bone mineral density, (2) loss of trabecular bone volume, thickness, number, and increased separation, (3) loss of cortical area and thickness, and 4) reduced bone stiffness and strength. These findings predominately relate the tibia/femur of young/mature female mice, however, their deconditioning response appeared similar, but not identical, to male rats. A dose-response trend was frequently observed between the magnitude of deconditioning and PWB level. The deconditioning patterns in PWB resembled those in rodents and humans exposed to microgravity and microgravity analogs. The present findings suggest that countermeasures against bone deconditioning may be required for humans exploring the Lunar and Martian surfaces.

The Effects of Reconditioning Exercises Following Prolonged Bed Rest on Lumbopelvic Muscle Volume and Accumulation of Paraspinal Muscle Fat.

Reduced muscle size and accumulation of paraspinal muscle fat content (PFC) have been reported in lumbopelvic muscles after spaceflights and head-down tilt (HDT) bed rest. While some information is available regarding reconditioning programs on muscle atrophy recovery, the effects on the accumulation of PFC are unknown. Recently, a device (the Functional Re-adaptive Exercise Device-FRED) has been developed which aims to specifically recruit lumbopelvic muscles. This study aimed to investigate the effects of a standard reconditioning (SR) program and SR program supplemented by FRED (SR + FRED) on the recovery of the lumbopelvic muscles following 60-day HDT bed rest. Twenty-four healthy participants arrived at the facility for baseline data collection (BDC) before the bed rest period. They remained in the facility for 13-day post-HDT bed rest and were randomly allocated to one of two reconditioning programs: SR or SR + FRED. Muscle volumes of the lumbar multifidus (LM), lumbar erector spinae (LES), quadratus lumborum (QL), and psoas major (PM) muscles were measured from axial T1-weighted magnetic resonance imaging (MRI) at all lumbar intervertebral disc levels. PFC was determined using a chemical shift-based lipid/water Dixon sequence. Each lumbopelvic muscle was segmented into four equal quartiles (from medial to lateral). MRI of the lumbopelvic region was conducted at BDC, Day-59 of bed rest (HDT59), and Day-13 after reconditioning (R13). Comparing R13 with BDC, the volumes of the LM muscle at L4/L5 and L5/S1, LES at L1/L2, and QL at L3/L4 had not recovered (all-p < 0.05), and the PM muscle remained larger at L1/L2 (p = 0.001). Accumulation of PFC in the LM muscle at the L4/L5 and L5/S1 levels remained higher in the centro-medial regions at R13 than BDC (all-p < 0.05). There was no difference between the two reconditioning programs. A 2-week reconditioning program was insufficient to fully restore all volumes of lumbopelvic muscles and reverse the accumulation of PFC in the muscles measured to BDC values, particularly in the LM muscle at the lower lumbar levels. These findings suggest that more extended reconditioning programs or alternative exercises may be necessary to fully restore the size and properties of the lumbopelvic muscles after prolonged bed rest.

Intramuscular lipid concentration increased in localized regions of the lumbar muscles following 60 day bedrest.

BACKGROUND CONTEXT: Prolonged bedrest induces accumulation of intramuscular lipid concentration (ILC) in the lumbar musculature; however, spatial distribution of ILC has not been determined. Artificial gravity (AG) mitigates some adaptations induced by 60 day bedrest by creating a head-to-feet force while participants are in a supine position. PURPOSE: To quantify the spatial distribution of accumulation of ILC in the lumbar musculature after 60 day bedrest, and whether this can be mitigated by AG exposure. STUDY DESIGN: Prospective longitudinal study. PATIENT SAMPLE: Twenty-four healthy individuals (8 females) participated in the study: Eight received 30 min continuous AG (cAG); Eight received 6 × 5 min AG (iAG), interspersed with rests; Eight were not exposed to AG (CRTL). OUTCOME MEASURES: From 3T magnetic resonance imaging (MRI), axial images were selected to assess lumbar multifidus (LM), lumbar erector spinae (LES), quadratus lumborum (QL), and psoas major (PM) muscles from L1/L2 to L5/S1 intervertebral disc levels. Chemical shift-based 2-echo lipid and/or water Dixon sequence was used to measure tissue composition. Each lumbar muscle was segmented into four equal quartiles (from medial to lateral). METHODS: Participants arrived at the facility for the baseline data collection before undergoing a 60 day strict 6° head-down tilt (HDT) bedrest period. MRI of the lumbopelvic region was conducted at baseline and Day-59 of bedrest. Participants performed all activities, including hygiene, in 6° HDT and were discouraged from moving excessively or unnecessarily. RESULTS: At the L4/L5 and L5/S1 intervertebral disc levels, 60-day bedrest induced a greater increase in ILC in medial and lateral regions (∼+4%) of the LM than central regions (∼+2%; p<.05). A smaller increase in ILC was induced in the lateral region of LES (∼+1%) at L1/L2 and L2/L3 than at the centro-medial region (∼+2%; p<.05). There was no difference between CRTL and intervention groups. CONCLUSIONS: Inhomogeneous spatial distribution of accumulation of ILC was found in the lumbar musculature after 60 day bedrest. These findings might reflect pathophysiological mechanisms related to muscle disuse and contribute to localized lumbar spine dysfunction. Altered spatial distribution of ILC may impair lumbar spine function after prolonged body unloading, which could increase injury risk to vulnerable soft tissues, such as the lumbar intervertebral discs. These novel results may represent a new biomarker of lumbar deconditioning for astronauts, bedridden, sedentary individuals, or those with chronic back pain. Changes are potentially modifiable but not by the AG protocols tested here.

Cell-based therapies for the treatment of sports injuries of the upper limb.

Introduction: The use of cell-based therapies in the management of sports injuries of the upper limb is increasingly popular despite the limited scientific evidence available for their use. We aim to evaluate the evidence for the use of cell-based therapies in these injuries and recommend areas for further research.Areas covered: In accordance with a published protocol (PROSPERO; Registration No. CRD42020193258), a comprehensive search of the literature was performed using the MEDLINE and EMBASE databases from inception to June 2020. All human studies reporting on the clinical, histological, or radiological outcomes following the use of cell-based therapies in the management of epicondylitis or rotator cuff pathology were included in this study. This resulted in 22 studies being included in this review, all of which underwent risk of bias assessments.Expert opinion: The evidence for the use of cell-based therapies in upper limb sports injuries is limited and generally of low quality. Given the heterogeneity in the cell types used, their harvesting methods and cell amounts, future research should be targeted at developing standardization of the reporting of these studies and more direct comparative studies looking at the efficacy of the different cell types.

Developing, Implementing, and Applying Novel Techniques During Systematic Reviews of Primary Space Medicine Data.

BACKGROUND: The Aerospace Medicine Systematic Review Group was set up in 2016 to facilitate high quality and transparent synthesis of primary data to enable evidence-based practice. The group identified many research methods specific to space medicine that need consideration for systematic review methods. The group has developed space medicine specific methods to address this and trialed usage of these methods across seven published systematic reviews. This paper outlines evolution of space medicine synthesis methods and discussion of their initial application.METHODS: Space medicine systematic review guidance has been developed for protocol planning, quantitative and qualitative synthesis, sourcing gray data, and assessing quality and transferability of space medicine human spaceflight simulation study environments.RESULTS: Decision algorithms for guidance and tool usage were created based on usage. Six reviews used quantitative methods in which no meta-analyses were possible due to lack of controlled trials or reporting issues. All reviews scored the quality and transferability of space simulation environments. One review was qualitative. Several research gaps were identified.CONCLUSION: Successful use of the developed methods demonstrates usability and initial validity. The current space medicine evidence base resulting in no meta-analyses being possible shows the need for standardized guidance on how to synthesize data in this field. It also provides evidence to call for increasing use of controlled trials, standardizing outcome measures, and improving minimum reporting standards. Space medicine is a unique field of medical research that requires specific systematic review methods.Winnard A, Caplan N, Bruce-Martin C, Swain P, Velho R, Meroni R, Wotring V, Damann V, Weber T, Evetts S, Laws J. Developing, implementing, and applying novel techniques during systematic reviews of primary space medicine data. Aerosp Med Hum Perform. 2021; 92(8):681688.

Gluteal Muscle Atrophy and Increased Intramuscular Lipid Concentration Are Not Mitigated by Daily Artificial Gravity Following 60-Day Head-Down Tilt Bed Rest.

Exposure to spaceflight and head-down tilt (HDT) bed rest leads to decreases in the mass of the gluteal muscle. Preliminary results have suggested that interventions, such as artificial gravity (AG), can partially mitigate some of the physiological adaptations induced by HDT bed rest. However, its effect on the gluteal muscles is currently unknown. This study investigated the effects of daily AG on the gluteal muscles during 60-day HDT bed rest. Twenty-four healthy individuals participated in the study: eight received 30 min of continuous AG; eight received 6 × 5 min of AG, interspersed with rest periods; eight belonged to a control group. T1-weighted Dixon magnetic resonance imaging of the hip region was conducted at baseline and day 59 of HDT bed rest to establish changes in volumes and intramuscular lipid concentration (ILC). Results showed that, across groups, muscle volumes decreased by 9.2% for gluteus maximus (GMAX), 8.0% for gluteus medius (GMED), and 10.5% for gluteus minimus after 59-day HDT bed rest (all p < 0.005). The ILC increased by 1.3% for GMAX and 0.5% for GMED (both p < 0.05). Neither of the AG protocols mitigated deconditioning of the gluteal muscles. Whereas all gluteal muscles atrophied, the ratio of lipids to intramuscular water increased only in GMAX and GMED muscles. These changes could impair the function of the hip joint and increased the risk of falls. The deconditioning of the gluteal muscles in space may negatively impact the hip joint stability of astronauts when reexpose to terrestrial gravity.

Lumbar muscle atrophy and increased relative intramuscular lipid concentration are not mitigated by daily artificial gravity after 60-day head-down tilt bed rest.

Exposure to axial unloading induces adaptations in paraspinal muscles, as shown after spaceflights. This study investigated whether daily exposure to artificial gravity (AG) mitigated lumbar spine flattening and muscle atrophy associated with 60-day head-down tilt (HDT) bed rest (Earth-based space analog). Twenty-four healthy individuals participated in the study: 8 received 30-min continuous AG; 8 received 6 × 5-min AG interspersed with rest periods; and 8 received no AG exposure (control group). Magnetic resonance imaging (MRI) of the lumbopelvic region was conducted at baseline (BDC) and at day 59 of HDT (HDT59). Longitudinal relaxation time (T1)-weighted images were used to assess morphology of the lumbar spine (spinal length, intervertebral disk angles, disk area) and volumes of the lumbar multifidus (LM), lumbar erector spinae (LES), quadratus lumborum (QL), and psoas major (PM) muscles from L1/L2 to L5/S1 vertebral levels. A chemical shift-based two-point lipid/water Dixon sequence was used to evaluate muscle composition. Results showed that spinal length and disk area increased (P < 0.05); intervertebral disk angles (P < 0.05) and muscle volumes of LM, LES, and QL reduced (P < 0.01); and lipid-to-water ratio for the LM and LES muscles increased (P < 0.01) after HDT59 in all groups. Neither of the AG protocols mitigated the lumbar spinae deconditioning induced by HDT bed rest. The increase in lipid-to-water ratio in LM and LES muscles indicates an increased relative intramuscular lipid concentration. Altered muscle composition in atrophied muscles may impair lumbar spine function after body unloading, which could increase injury risk to vulnerable soft tissues. This relationship needs further investigation.NEW & NOTEWORTHY This study presents novel insights into the morphological adaptations occurring in the lumbar spine after 60-day head-down bed rest and the potential role of artificial gravity (AG) to mitigate them. Results demonstrated no protective effect of AG protocols used in this study. In atrophied paraspinal muscles, the ratio of lipids versus intramuscular water increased in the postural lumbar muscles, which could impair muscle function during upright standing. These findings have relevance for future space explorations.

Intermittent short-arm centrifugation is a partially effective countermeasure against upright balance deterioration following 60-day head-down tilt bed rest.

This study investigated whether artificial gravity (AG), induced by short-radius centrifugation, mitigated deterioration in standing balance and anticipatory postural adjustments (APAs) of trunk muscles following 60-day head-down tilt bed rest. Twenty-four participants were allocated to one of three groups: control group (n = 8); 30-min continuous AG daily (n = 8); and intermittent 6 × 5 min AG daily (n = 8). Before and immediately after bed rest, standing balance was assessed in four conditions: eyes open and closed on both stable and foam surfaces. Measures including sway path, root mean square, and peak sway velocity, sway area, sway frequency power, and sway density curve were extracted from the center of pressure displacement. APAs were assessed during rapid arm movements using intramuscular or surface electromyography electrodes of the rectus abdominis; obliquus externus and internus abdominis; transversus abdominis; erector spinae at L1, L2, L3, and L4 vertebral levels; and deep lumbar multifidus muscles. The relative latency between the EMG onset of the deltoid and each of the trunk muscles was calculated. All three groups had poorer balance performance in most of the parameters (all P < 0.05) and delayed APAs of the trunk muscles following bed rest (all P < 0.05). Sway path and sway velocity were deteriorated, and sway frequency power was less in those who received intermittent AG than in the control group (all P < 0.05), particularly in conditions with reduced proprioceptive feedback. These data highlight the potential of intermittent AG to mitigate deterioration of some aspects of postural control induced by gravitational unloading, but no protective effects on trunk muscle responses were observed.NEW & NOTEWORTHY This study presents novel insights into the effect of artificial gravity (AG) on the deterioration of standing balance and anticipatory postural adjustments (APAs) of trunk muscles induced by 60-day strict head-down bed rest. The results indicated severe balance dysfunction and delayed APAs during rapid arm movement. AG partially mitigated the deterioration in standing balance and may thus be considered as a potential countermeasure for future planetary surface explorations. Optimization of AG protocols might enhance effects.

Fatigue Induced Changes in Muscle Strength and Gait Following Two Different Intensity, Energy Expenditure Matched Runs.

PURPOSE: To investigate changes in hip and knee strength, kinematics, and running variability following two energy expenditure matched training runs; a medium intensity continuous run (MICR) and a high intensity interval training session (HIIT). METHODS: Twenty (10 Females, 10 Males) healthy master class runners were recruited. Each participant completed the HIIT consisting of six repetitions of 800 m with a 1:1 work: rest ratio. The MICR duration was set to match energy expenditure of the HIIT session. Hip and knee muscular strength were examined pre and post both HIIT and MICR. Kinematics and running variability for hip and knee, along with spatiotemporal parameters were assessed at start and end of each run-type. Changes in variables were examined using both 2 × 2 ANOVAs with repeated measures and on an individual level when the change in a variable exceeded the minimum detectable change (MDC). RESULTS: All strength measures exhibited significant reductions at the hip and knee (P < 0.05) with time for both run-types; 12% following HIIT, 10.6% post MICR. Hip frontal plane kinematics increased post run for both maximum angle (P < 0.001) and range of motion (P = 0.003). Runners exhibited increased running variability for nearly all variables, with the HIIT having a greater effect. Individual assessment revealed that not all runners were effected post run and that following HIIT more runners had reduced muscular strength, altered kinematics and increased running variability. CONCLUSION: Runners exhibited fatigue induced changes following typical training runs, which could potentially present risk of injury development. Group and individual assessment revealed different findings where the use of MDC is recommended over that of P-values.