Musculoskeletal Recovery Research Articles

A 9-week (beginner) recreational runner training program for 5 km distance

ABSTRACT The popularity of running is increasing worldwide with increased awareness of general well-being among people of all ages. Being easily accessible and with only a pair of shoes needed, many recreational runners practice this sport away from competitions. This review aims to illustrate a 9-week training program for the novice recreational runner to run for 5 km. The training program is designed according to runners’ physiological and biomechanical requirements. Strength and endurance training are combined on nonconsecutive six days per week. The strength training aims to strengthen upper limbs, lower limbs, and core muscles depending solely on body weight with no extra load since endurance runners do not require the power component or direction changes. The endurance training is structured to improve the maximal oxygen uptake and running economy to avoid rapid fatigue. The program also offers a warming-up routine to promote body preparation for physical activity to minimize the risk of injuries, in addition to cooling-down prescriptions to enhance musculoskeletal recovery and future performance. On the seventh day of the week, the runner can choose between active recovery exercise or complete rest. Active recovery is recommended to maintain the physiological attributes gained from the combined strength and endurance training.

Adaptation to full weight-bearing following disuse in rats: The impact of biological sex on musculoskeletal recovery.

With the technological advances made to expand space exploration, astronauts will spend extended amounts of time in space before returning to Earth. This situation of unloading and reloading influences human physiology, and readaptation to full weight-bearing may significantly impact astronauts' health. On Earth, similar situations can be observed in patients who are bedridden or suffer from sport-related injuries. However, our knowledge of male physiology far exceeds our knowledge of female's, which creates an important gap that needs to be addressed to understand the sex-based differences regarding musculoskeletal adaptation to unloading and reloading, necessary to preserve health of both sexes. Using a ground-based model of total unloading for 14 days and reloading at full weight-bearing for 7 days rats, we aimed to compare the musculoskeletal adaptations between males and females. Our results reveal the existence of significant differences. Indeed, males experienced bone loss both during the unloading and the reloading period while females did not. During simulated microgravity, males and females showed comparable muscle deconditioning with a significant decline in rear paw grip strength. However, after 7 days of recovery, muscle strength improved. Additionally, sex-based differences in myofiber size existing at baseline are significantly reduced or eliminated following unloading and recovery.

GDF8 inhibition enhances musculoskeletal recovery and mitigates posttraumatic osteoarthritis following joint injury.

Musculoskeletal disorders contribute substantially to worldwide disability. Anterior cruciate ligament (ACL) tears result in unresolved muscle weakness and posttraumatic osteoarthritis (PTOA). Growth differentiation factor 8 (GDF8) has been implicated in the pathogenesis of musculoskeletal degeneration following ACL injury. We investigated GDF8 levels in ACL-injured human skeletal muscle and serum and tested a humanized monoclonal GDF8 antibody against a placebo in a mouse model of PTOA (surgically induced ACL tear). In patients, muscle GDF8 was predictive of atrophy, weakness, and periarticular bone loss 6 months following surgical ACL reconstruction. In mice, GDF8 antibody administration substantially mitigated muscle atrophy, weakness, and fibrosis. GDF8 antibody treatment rescued the skeletal muscle and articular cartilage transcriptomic response to ACL injury and attenuated PTOA severity and deficits in periarticular bone microarchitecture. Furthermore, GDF8 genetic deletion neutralized musculoskeletal deficits in response to ACL injury. Our findings support an opportunity for rapid targeting of GDF8 to enhance functional musculoskeletal recovery and mitigate the severity of PTOA after injury.

Juvenile zebrafish (Danio rerio) are able to recover from lordosis

Haemal lordosis, a frequent skeletal deformity in teleost fish, has long been correlated with increased mechanical loads induced by swimming activity. In the present study, we examine whether juvenile zebrafish can recover from haemal lordosis and explore the musculoskeletal mechanisms involved. Juveniles were subjected to a swimming challenge test (SCT) that induced severe haemal lordosis in 49% of the animals and then immediately transferred them to 0.0 total body lengths (TL) per second of water velocity for a week. The recovery from lordosis was examined by means of whole mount staining, histology and gene expression analysis. Results demonstrate that 80% of the lordotic zebrafish are capable of internal and external recovery within a week after the SCT. Recovered individuals presented normal shape of the vertebral centra, maintaining though distorted internal tissue organization. Through the transcriptomic analysis of the affected haemal regions, several processes related to chromosome organization, DNA replication, circadian clock and transcription regulation were enriched within genes significantly regulated behind this musculoskeletal recovery procedure. Genes especially involved in adipogenesis, bone remodeling and muscular regeneration were regulated. A remodeling tissue-repair hypothesis behind haemal lordosis recovery is raised. Limitations and future possibilities for zebrafish as a model organism to clarify mechanically driven musculoskeletal changes are discussed.

Grip strength in children after non-severe burn injury

PurposeTo characterise grip strength in children with non-severe burn injury, and further understanding of how demographic and clinical variables impact musculoskeletal recovery. MethodsA retrospective, cross-sectional audit of routinely collected clinical data was performed. Standardised protocols were used to measure height, weight and grip strength. Demographic and clinical information was collected from patient medical records. Grip strength comparisons were made against normative data using paired t-tests. General linear regressions with backwards elimination were performed to assess impact of clinical, demographic and physical variables on grip strength. ResultsChildren who were right hand (RH) dominant had reduced RH (18.9 ± 9.9 kg, p = 0.001) and left hand (LH)(17.6 ± 9.3 kg, p = 0.027) grip strength compared to age, sex and hand-dominance matched norms (RH, 20.0 ± 10.0 kg; LH, 18.4 ± 9.5 kg). Children who were assessed closer to the time of their injury, and those who were burnt at a young age were more likely to score grip strength values below the norm (p < 0.001 for all analyses). In particular, females appeared to be at a higher risk of low grip strength scores if burnt at a young age (p < 0.001). ConclusionsChildren with non-severe burn injury struggle to recover musculoskeletal strength, with those who were assessed closer to the time of injury or burnt at a young age especially at risk of impaired grip strength performance. Grip strength does not appear to be influenced by any other clinical variables or burn injury characteristics.

Effects of horse housing on musculoskeletal system post-exercise recovery

This study examined the effects of two housing systems (control housing and loose housing) on musculoskeletal condition during recovery from race-like exercise in Standardbred horses. The hypothesis was that a loose housing system provides better conditions for musculoskeletal recovery than the control housing. Eight adult geldings (mean age 11 years) were used in a study with a cross-over design, with the control housing (CH) and loose housing (LH) treatments each run for 21 days. The horses had ad libitum access to forage and performed two similar race-like exercise tests (ET), on day 7 and day 14 in each treatment. Blood samples were collected before ET, at finish line, and at 7, 22, and 44 h of recovery and analysed for the muscle enzyme activities of creatine kinase and amino transferase. Before and three days after ET, hind leg fetlock joint region circumference and diameter, joint range of motion in right hock and carpus, mechanical nociceptive threshold in back muscle, and movement asymmetry were recorded. Overall circumference and overall diameter of hind fetlock joint region were lower in LH horses than CH horses (P=0.045 and P=0.017, respectively), but no other differences were observed. In conclusion, a loose housing system did not alter the recovery of musculoskeletal condition other than preventing a post exercise enlargement of the circumference and diameter of the hind fetlock joint region.

314 Alcohol and the Sleep of Elite Athletes

Abstract Introduction Extensive evidence indicates that alcohol adversely affects athletic performance, increases the chance of injury, impairs aerobic metabolism, and has detrimental psychological influence. Alcohol consumption was also shown to be significant in young adults, with many elite athletes reporting alcohol intake. Sleep is essential to musculoskeletal recovery, acquisition of new skills, and emotional regulation in athletes. As insufficient sleep has detrimental effects on athletic performances and increases the risk of injury, we aimed to analyze the relation between alcohol consumption and sleep parameters among elite athletes. Methods We studied 9,164 nights recorded with the Boost application by 66 adult elite athletes from various sports during October 2019-December 2020. In addition to perceived and measured sleep parameters, nightly data included the previous day reported alcohol consumption and the number of training sessions. For each athlete, the average nightly mean heart rate (HR) in nights with reported alcohol consumption (AY) and without (AN) was calculated, as were the bedtime and the number of training sessions. Results In nights with reported alcohol, mean HR was higher (AY: 56.1±7.8 BPM, mean±SD, AN: 52.9±7.3 BPM, p&amp;lt;.05), while bedtime was later (AY: 23:16±70 minutes, AN: 22:52±55 minutes, p&amp;lt;.05) and fewer training sessions were reported in the following day (AY: 0.88±0.59 sessions, AN: 1.1±0.59 sessions, p&amp;lt;.05). No correlation was found between mean HR and bedtime in nights without alcohol consumption (r=0.3). 24% of Saturday night recordings included alcohol consumption reports, with 16% of Friday nights and 12–13% for each of the remaining weeknights. Conclusion Adult elite athletes report consuming alcohol, especially during weekends when the probability for a training session the following day is lower. Our data support the well documented physiological effect of alcohol via elevated mean HR values throughout the night. Athletes and coaches should be educated about the impacts of alcohol and insufficient sleep on wellbeing and performance. Support (if any):

A narrative review of the research progress and clinical application of platelet-rich plasma.

As a traditional treatment invented in the 1970s, the usage of platelet-rich plasma (PRP) has been reported constantly in many medical areas, such as tissue regeneration, wound healing, ligament repair, hair loss, and so on. In this review, we focus on the administration of PRP in musculoskeletal recovery. As a part of autogenous blood plasma, PRP's platelet concentration is above the baseline. It is extracted from the host's blood sample collected before centrifugal separation. The history, mechanism and preparation of PRP, and existing clinical applications of it will become a helper for clinicians to better understand this therapy. However, the molecular mechanism of PRP treatment is still under debate. On the other hand, because of the safety concern during the PRP's preparation, the practical application of PRP is only applied in many rare cases, especially in spinal diseases. In this paper, we attempt to make a better understanding of the mechanism of PRP and the preparation of PRP; meanwhile, to raise existing questions about further application of PRP in the future. We recommend that PRP should be used in spinal diseases and other fields and in the future we ought to find a safe, simple, and standardized PRP preparation protocol.

Effects of Collagen Peptides on Recovery Following Eccentric Exercise in Resistance-Trained Males-A Pilot Study.

The authors sought to determine whether consuming collagen peptides (CP) enhances musculoskeletal recovery of connective tissues following a damaging exercise bout. Resistance-trained males consumed 15g/day of CP (n = 7) or placebo (n = 8), and after 7days, maximal voluntary isometric contraction (MVIC), countermovement jump height, soreness, and collagen turnover were examined. Five sets of 20 drop jumps were performed and outcome measures were collected 24, 48, and 120hr postexercise. Countermovement jump height was maintained in the CP group at 24hr (PRE = 39.9 ± 8.8cm vs. 24hr = 37.9 ± 8.9cm, p = .102), whereas the CP group experienced a significant decline at 24hr (PRE = 40.4 ± 7.9cm vs. 24hr = 35.5 ± 6.4cm, p = .001; d = 0.32). In both groups, muscle soreness was significantly higher than PRE at 24hr (p = .001) and 48hr (p = .018) but not at 120hr (p > .05). MVIC in both legs showed a significant time effect (left: p = .007; right: p = .010) over the 5-day postexercise period. Neither collagen biomarker changed significantly at any time point. CP supplementation attenuated performance decline 24hr following muscle damage. Acute consumption of CP may provide a performance benefit the day following a bout of damaging exercise in resistance-trained males.

Does photobiomodulation therapy combined to static magnetic field (PBMT-sMF) promote ergogenic effects even when the exercised muscle group is not irradiated? A randomized, triple-blind, placebo-controlled trial

BackgroundThe direct application of photobiomodulation therapy (PBMT) using low-level laser therapy (LLLT) and light emitting diodes (LEDs) combined with a static magnetic field (sMF) (PBMT-sMF) to target tissues is shown to improve muscle performance and recovery. Studies have reported possible PBMT effects when a local distant to the target tissue is irradiated. Notably, the extent of these effects on musculoskeletal performance and the optimal site of irradiation remain unclear, although this information is clinically important since these aspects could directly affect the magnitude of the effect. Therefore, we investigated the effects of local and non-local PBMT-sMF irradiations on musculoskeletal performance and post-exercise recovery before an eccentric exercise protocol.MethodsThis randomized, triple-blind (participants, therapists and assessors), placebo-controlled trial included 30 healthy male volunteers randomly assigned to the placebo, local, and non-local groups. Active or placebo PBMT-sMF was applied to 6 sites of the quadriceps muscle of both legs. An eccentric exercise protocol was used to induce fatigue. The primary outcome was peak torque assessed by maximal voluntary contraction (MVC). The secondary outcomes were delayed onset muscle soreness (DOMS) measured by visual analogue scale (VAS), muscle injury assessed by serum creatine kinase activity (CK), and blood lactate levels. Evaluations were performed before the eccentric exercise protocol (baseline), as well as immediately after and 1, 24, 48, and 72 h upon protocol completion.ResultsTen volunteers were randomized per group and analysed for all outcomes. Compared to the placebo and non-local groups, irradiation with PBMT-SMF led to statistically significant improvement (p < 0.05) with regard to all variables in the local group. The outcomes observed in the non-local group were similar to those in the placebo group with regard to all variables.The volunteers did not report any adverse effects.ConclusionOur results support the current evidence that local irradiation of all exercised muscles promotes ergogenic effects. PBMT-sMF improved performance and reduced muscle fatigue only when applied locally to muscles involved in physical activity.Trial registrationNCT03695458. Registered October 04th 2018.

0206 Sleep Opportunity and Duration are Related to Risk Injury in Elite Athletes

Abstract Introduction Sleep is essential to musculoskeletal recovery, acquisition of new skills and emotional regulation in athletes. Insufficient sleep is detrimental to performance. Recent publications indicate that sleep duration is related to risk for injury in young athletes. We aimed at analyzing the relation between sleep opportunity and duration and the likelihood of an injury among adult elite athletes. Methods We studied 7,237 nights recorded with the Sleeprate application by 71 adult elite athletes from diverse sports, during the period September 2018-October 2019. Night recordings included perceived and measured sleep parameters. In addition, athletes reported their previous day nap duration, injuries and illness status. Out of the total number of nights, 4,205 included reported injury status with no injury and no illness for the previous night. Nightly total time in bed (TIB), TIB including reported naps (TIB24hr) and measured total sleep time (TST) were examined. Results Average TIB was significantly shorter (508±77 minutes, mean±STD) in healthy days preceding injuries than in healthy days preceding days with no injury (525±70 minutes, p&amp;lt;.001). Similar results were found when comparing the TIB24hr (injury: 517±83 minutes, no injury: 543±76 minutes, p&amp;lt;.001) and TST (injury: 443±72 minutes, no injury: 457±69 minutes, p&amp;lt;.001). Conclusion Average sleep opportunities of the elite athletes in this study were in accordance with their age and workouts load. The time athletes allow themselves as an opportunity for sleep is inversely correlated to the chances of developing an injury. These findings corroborate published research regarding sleep duration and risk of injury in athletes, yet our findings are based on real life data of elite athletes, and demonstrate the importance of sleep as part of the elite or professional athlete’s routine, suggesting that even as little as around 20 minutes of added sleep may be efficient in preventing injury. Support N/A

Locomotor training with adjuvant testosterone preserves cancellous bone and promotes muscle plasticity in male rats after severe spinal cord injury.

Loading and testosterone may influence musculoskeletal recovery after spinal cord injury (SCI). Our objectives were to determine (a) the acute effects of bodyweight-supported treadmill training (TM) on hindlimb cancellous bone microstructure and muscle mass in adult rats after severe contusion SCI and (b) whether longer-term TM with adjuvant testosterone enanthate (TE) delivers musculoskeletal benefit. In Study 1, TM (40 min/day, 5 days/week, beginning 1 week postsurgery) did not prevent SCI-induced hindlimb cancellous bone loss after 3 weeks. In Study 2, TM did not attenuate SCI-induced plantar flexor muscles atrophy nor improve locomotor recovery after 4 weeks. In our main study, SCI produced extensive distal femur and proximal tibia cancellous bone deficits, a deleterious slow-to-fast fiber-type transition in soleus, lower muscle fiber cross-sectional area (fCSA), impaired muscle force production, and levator ani/bulbocavernosus (LABC) muscle atrophy after 8 weeks. TE alone (7.0 mg/week) suppressed bone resorption, attenuated cancellous bone loss, constrained the soleus fiber-type transition, and prevented LABC atrophy. In comparison, TE+TM concomitantly suppressed bone resorption and stimulated bone formation after SCI, produced near-complete cancellous bone preservation, prevented the soleus fiber-type transition, attenuated soleus fCSA atrophy, maintained soleus force production, and increased LABC mass. 75% of SCI+TE+TM animals recovered voluntary over-ground hindlimb stepping, while no SCI and only 20% of SCI+TE animals regained stepping ability. Positive associations between testosterone and locomotor function suggest that TE influenced locomotor recovery. In conclusion, short-term TM alone did not improve bone, muscle, or locomotor recovery in adult rats after severe SCI, while longer-term TE+TM provided more comprehensive musculoskeletal benefit than TE alone.

Social Determinants of Health: If You Aren't Measuring Them, You Aren't Seeing the Big Picture.

Clinicians often assume that interventions directly influence the recovery of patients with musculoskeletal impairments. In reality, other factors may influence recovery more than the direct treatment provided. The most powerful factor may be upstream effects such as economic stability, education, health and health care, neighborhood and built environment, and social and community context-commonly termed the social determinant of health (SDH). Although a single empirical pathway linking the collective impacts of the SDH to musculoskeletal health outcomes has not been established, our view is that they exert tremendous effects on physical therapy outcomes in practice and research. In this Viewpoint, the authors discuss the SDH and argue that recognizing the impact of SDHs on health behavior is vital to seeing the whole picture related to musculoskeletal recovery. J Orthop Sports Phys Ther 2019;49(12):872-874. doi:10.2519/jospt.2019.0613.

Changes in Nutritional Status and Musculoskeletal Health in a Geriatric Post-Fall Care Plan Setting.

Understanding how changes in nutritional status influence musculoskeletal recovery after falling remains unclear. We explored associations between changes in nutritional status and musculoskeletal health in 106 community-dwelling older adults aged ≥65 years, who attended the Falls and Fractures Clinic at Sunshine Hospital in St Albans, Australia after falling. At baseline and after 6 months, individuals were assessed for Mini Nutritional Assessment (MNA®), grip strength, gait speed, Timed Up and Go (TUG) test, Short Physical Performance Battery (SPPB), and bone turnover marker levels. Associations were examined using multiple linear regression, adjusted for baseline covariates and post-fall care plans. Over 6 months, the prevalence of malnutrition or risk thereof decreased from 29% to 15% using MNA <24/30. Specifically, 20 individuals (19%) improved, 7 (7%) deteriorated, and 73 (69%) maintained nutritional status, including 65 (61%) who remained well-nourished and 8 (8%) who remained malnourished/at risk. A 1-point increase in MNA score over 6 months was associated with an increase of 0.20 points (95% confidence interval 0.10, 0.31, p < 0.001) in SPPB score. Improvement in nutritional status was associated with improvement in physical performance, providing a basis for interventional studies to ascertain causality and evaluate nutritional models of care for post-fall functional recovery in older adults.

The effect of preoperative respiratory physiotherapy and motor exercise in patients undergoing elective cardiac surgery: short-term results.

IntroductionLoss of physical activity and pulmonary dysfunction with its associated complications represent two of the most important causes of morbidity and mortality following cardiac surgery. Few studies have investigated the effects of preoperative interventions targeted at improving cardiorespiratory and musculoskeletal function in the postoperative period.AimTo evaluate whether a physiotherapy program based on respiratory training with or without musculoskeletal mobilization, started preoperatively, may provide a significant improvement in pulmonary and musculoskeletal recovery postoperatively in patients undergoing elective cardiac surgery.Material and methodsPatients with similar baseline and preoperative characteristics were randomly assigned to a preoperative respiratory physiotherapy protocol (group A), a preoperative respiratory and motor physiotherapy protocol (group B), or no preoperative specific physiotherapy protocol but only a simplified perioperative standard physiotherapy protocol (control group or group C). Group A consisted of 19 patients, group B of 20, group C of 20. Data on 6-minute walking test, peak expiratory flow, and from blood gas analysis were retrospectively analyzed.ResultsAs compared with group C, a statistically significant improvement was observed in the two preoperatively treated groups A and B in terms of longer pre- and postoperative distance traveled at the 6-minute walking test, better pre- and postoperative peak expiratory flow value, and better PaO2 and SaO2 values in postoperative blood gas measurements (p < 0.05, for all comparisons). A statistically significant reduction of the postoperative length of in-hospital stay was also observed in group B.ConclusionsAs compared with the control group, substantially better clinical results for respiratory and musculoskeletal function were found in the groups preoperatively treated with physiotherapeutic protocols immediately before as well as after cardiac surgery.

Bone marrow lesions of the knee: longitudinal correlation between lesion size changes and pain before and after conservative treatment by extracorporeal shockwave therapy.

Bone marrow lesions (BMLs) of the knee have become a common finding on magnetic resonance imaging (MRI), leading to a growing interest in BML, not only for its potential role in the progression of several musculoskeletal conditions, but also for its clinical impact and treatment implications. At present, there is limited and conflicting evidence regarding whether or not pain may be correlated to BML size or not. To verify the longitudinal correlation between BML size and knee pain. Longitudinal. Italian Orthopedic Institute. The study sample was composed of 72 patients, 27 males and 45 females, with a mean age of 55.9±10.22 years and a mean BMI of 26.1±3.7 kg/m2. All patients presented with BMLs and acute knee pain. All 72 patients underwent a knee MRI before and 6 months after a course of high energy ESWT, in order to perform a quantitative measurement of the BML areas. KOOS (Knee Injury and Osteoarthritis Outcome Score) Pain subscale scores were obtained at the same time point. A regression analysis was performed to verify the correlation between knee BML size and KOOS pain subscale score before treatment and the correlation between the reduction of BML size and the improvement of KOOS pain score 6 months after treatment. A statistically significant correlation between the KOOS Pain subscale and the BML size (beta=-0.362 [CI95%: -0.019/-0.05], P=0.002) was demonstrated. The clinical score and BML area significantly improved after treatment (P<0.001). The clinical improvement was correlated to the BML size reduction (beta=0.254 [CI95%: 0.001/0.017], P=0.031). This study confirmed a significant correlation between the BML size and the intensity of knee pain. Furthermore, the before and after study using ESWT to treat symptomatic BMLs, revealed a correlation between size reduction of BML and KOOS pain subscale score improvement, demonstrating the utility of BML reduction as a therapeutic goal. Finally, ESWT was validated as a safe and potentially effective treatment of subchondral bone marrow lesions. Our results confirm that severity of pain is correlated with BML size, and furthermore, demonstrate that increases and decreases in the amount of pain reflect growth or reduction in BML size, respectively. This information may be useful for rehabilitation and decrease the reliance on MRIs for checking the progress of bone lesions. Absence or marked reduction of pain should allow for the resumption of weight-bearing and more strenuous exercises for an adequate musculoskeletal recovery.

The Effects of Progressive Resistance Exercise on Recovery Rate of Bone and Muscle in a Rodent Model of Hindlimb Suspension.

Purpose: This study aimed to examine the exercise-mediated musculoskeletal recovery following hindlimb suspension (HS) in order to identify whether bone modeling and muscle hypertrophy would eventuate in a synchronized manner during recovery stage.Methods: To identify whether 2-week HS would be sufficient to induce a significant reduction of physiological indices in both tibia and adjacent hindlimb muscles, a total of 20 rats was randomized into 2-week HS (n = 10) and age-matched control group (n = 10, CON). Another batch of rats were randomly assigned to three different groups to identify recovery intervention effects following suspension: (1) 2-week HS followed by 4-week spontaneous reloading recovery (HRE, n = 7). (2) 2-week HS followed by 4-week progressive resistance ladder climbing exercise (HEX, n = 7). (3) Age-matched control (CON, n = 7). DXA, micro-CT, and 18F-sodium fluoride (NaF) imaging, and EIA analysis were utilized to measure tibia bone indices. Hindlimb muscle wet weight and grip strength were measured to evaluate muscle mass and strength, respectively.Results: In study 1, bone quality values [bone volume/total volume (BV/TV): -27%, areal bone mineral density (aBMD): -23%, mineral contents: -7.9%, mineral density: –4.1%, and bone density: -38.9%] and skeletal muscle weight (soleus: -46.8%, gastrocnemius: -19.6%, plantaris: -20.8%, TA: -22.8%, and EDL: -9.9%) were significantly lower in HS group compared to CON group. In study 2, micro-CT and DXA-based bone morphology (bone density, BT/TV, and aBMD) were fully recovered in HRE or HEX group. However, suspension-induced dysregulation of bone mineral metabolism was returned to age-matched control group in only HEX group, but not in HRE group. A greater level of biomarkers of bone formation (P1NF) and resorption (CTX-1) was observed in only HRE group compared to CON. The hindlimb skeletal muscle mass was significantly lower in both HRE and HEX groups compared to CON group. Hindlimb grip strength was the greatest in HEX group, followed by CON and HRE groups.Conclusion: Following HS, progressive resistance exercise promotes recovery rates of bone and skeletal muscle strength without a significant increase in muscular mass, suggesting that exercise-induced reacquisition of bone and muscle strength is independent of muscle hypertrophy during early recovery stage.

Activity-Based Physical Rehabilitation with Adjuvant Testosterone to Promote Neuromuscular Recovery after Spinal Cord Injury.

Neuromuscular impairment and reduced musculoskeletal integrity are hallmarks of spinal cord injury (SCI) that hinder locomotor recovery. These impairments are precipitated by the neurological insult and resulting disuse, which has stimulated interest in activity-based physical rehabilitation therapies (ABTs) that promote neuromuscular plasticity after SCI. However, ABT efficacy declines as SCI severity increases. Additionally, many men with SCI exhibit low testosterone, which may exacerbate neuromusculoskeletal impairment. Incorporating testosterone adjuvant to ABTs may improve musculoskeletal recovery and neuroplasticity because androgens attenuate muscle loss and the slow-to-fast muscle fiber-type transition after SCI, in a manner independent from mechanical strain, and promote motoneuron survival. These neuromusculoskeletal benefits are promising, although testosterone alone produces only limited functional improvement in rodent SCI models. In this review, we discuss the (1) molecular deficits underlying muscle loss after SCI; (2) independent influences of testosterone and locomotor training on neuromuscular function and musculoskeletal integrity post-SCI; (3) hormonal and molecular mechanisms underlying the therapeutic efficacy of these strategies; and (4) evidence supporting a multimodal strategy involving ABT with adjuvant testosterone, as a potential means to promote more comprehensive neuromusculoskeletal recovery than either strategy alone.

Impaired Trunk Flexor Strength, Fatigability, and Steadiness in Postpartum Women.

To determine whether postpartum women (vaginal and cesarean delivery) have deficits in trunk flexor strength, fatigability and steadiness, compared with nulligravid women, up to 26 wk postpartum. We hypothesized that postpartum women would be weaker, more fatigable, and have greater torque fluctuations than controls, with cesarean delivery showing greater deficits than vaginal delivery. Twenty-two control women (nulligravid) and 29 postpartum women (20-40 yr, 19 who delivered via vaginal birth, 13 via Caesarian section) participated. Postpartum women were tested 8 to 10 wk and 24 to 26 wk postpartum. Control women were tested 16 to 18 wk apart. Maximal voluntary isometric contractions (MVC) were performed at multiple trunk positions with the trunk flexor muscles. To determine trunk flexor fatigability, subjects performed intermittent isometric contractions at 50% MVC (6-s contraction, 4-s rest) in upright sitting until task failure. An MVC was performed during the fatiguing task (one per minute) and at 10 and 20 min of recovery. At 8 and 26 wk, postpartum women (groups pooled) were weaker at all trunk angles (38% and 44% respectively, P < 0.05) than controls despite no differences in handgrip strength. Postpartum women were more fatigable (71% and 52% respectively) and had greater torque fluctuations than controls (P < 0.05). At 8 wk postpartum, women who had a cesarean delivery, were 59% more fatigable (P = 0.004) than the vaginal delivery group, with no difference between delivery types at 26 wk postpartum. Musculoskeletal recovery, including trunk flexor muscle strength and fatigability, is incomplete at 26 wk postpartum. These findings provide a rationale for future studies to address outcomes of rehabilitation programs specifically targeted at improving strength and fatigability of the trunk flexor muscles after pregnancy and childbirth.

Design and Analysis of a Cable-Driven Articulated Rehabilitation System for Gait Training

Assisted motor therapies play a critical role in enhancing functional musculoskeletal recovery and neurological rehabilitation. Our long-term goal is to assist and automate the performance of repetitive motor-therapy of the human lower limbs. Hence, in this paper, we examine the viability of a light-weight and reconfigurable hybrid (articulated-multibody and cable) robotic system for assisting lower-extremity rehabilitation and analyze its performance. A hybrid cable-actuated articulated-multibody system is formed when multiple cables are attached from a ground-frame to various locations on an articulated-linkage-based orthosis. Our efforts initially focus on developing an analysis and simulation framework for the kinematics and dynamics of the cable-driven lower limb orthosis. A Monte Carlo approach is employed to select configuration parameters including cuff sizes, cuff locations, and the position of fixed winches. The desired motions for the rehabilitative exercises are prescribed based upon motion patterns from a normative subject cohort. We examine the viability of using two controllers—a joint-space feedback-linearized PD controller and a task-space force-control strategy—to realize trajectory- and path-tracking of the desired motions within a simulation environment. In particular, we examine performance in terms of (i) coordinated control of the redundant system; (ii) reducing internal stresses within the lower-extremity joints; and (iii) continued satisfaction of the unilateral cable-tension constraints throughout the workspace.