Manual therapy as an effective treatment for fibrosis in a rat model of upper extremity overuse injury

Key clinical features of carpal tunnel syndrome and other types of cumulative trauma disorders of the hand and wrist include pain and functional disabilities. Mechanistic details remain under investigation but may involve tissue inflammation and/or fibrosis. We examined the effectiveness of modeled manual therapy (MMT) as a treatment for sensorimotor behavior declines and increased fibrogenic processes occurring in forearm tissues of rats performing a high repetition high force (HRHF) reaching and grasping task for 12 weeks. Young adult, female rats were examined: food restricted control rats (FRC, n=12); rats that were trained for 6 weeks before performing the HRHF task for 12 weeks with no treatment (HRHF-CON, n=11); and HRHF task rats received modeled manual therapy (HRHF-MMT, n=5) for 5 days/week for the duration of the 12-week of task. Rats receiving the MMT expressed fewer discomfort-related behaviors, and performed progressively better in the HRHF task. Grip strength, while decreased after training, improved following MMT. Fibrotic nerve and connective tissue changes (increased collagen and TGF-β1 deposition) present in 12-week HRHF-CON rats were significantly decreased in 12-week HRHF-MMT rats. These observations support the investigation of manual therapy as a preventative for repetitive motion disorders.

Increased serum and musculotendinous fibrogenic proteins following persistent low-grade inflammation in a rat model of long-term upper extremity overuse

We examined the relationship between grip strength declines and muscle-tendon responses induced by long-term performance of a high-repetition, low-force (HRLF) reaching task in rats. We hypothesized that grip strength declines would correlate with inflammation, fibrosis and degradation in flexor digitorum muscles and tendons. Grip strength declined after training, and further in weeks 18 and 24, in reach limbs of HRLF rats. Flexor digitorum tissues of reach limbs showed low-grade increases in inflammatory cytokines: IL-1β after training and in week 18, IL-1α in week 18, TNF-α and IL-6 after training and in week 24, and IL-10 in week 24, with greater increases in tendons than muscles. Similar cytokine increases were detected in serum with HRLF: IL-1α and IL-10 in week 18, and TNF-α and IL-6 in week 24. Grip strength correlated inversely with IL-6 in muscles, tendons and serum, and TNF-α in muscles and serum. Four fibrogenic proteins, TGFB1, CTGF, PDGFab and PDGFbb, and hydroxyproline, a marker of collagen synthesis, increased in serum in HRLF weeks 18 or 24, concomitant with epitendon thickening, increased muscle and tendon TGFB1 and CTGF. A collagenolytic gelatinase, MMP2, increased by week 18 in serum, tendons and muscles of HRLF rats. Grip strength correlated inversely with TGFB1 in muscles, tendons and serum; with CTGF-immunoreactive fibroblasts in tendons; and with MMP2 in tendons and serum. Thus, motor declines correlated with low-grade systemic and musculotendinous inflammation throughout task performance, and increased fibrogenic and degradative proteins with prolonged task performance. Serum TNF-α, IL-6, TGFB1, CTGF and MMP2 may serve as serum biomarkers of work-related musculoskeletal disorders, although further studies in humans are needed.

Absence of the predisposing factors and signs and symptoms usually associated with overreaching and overtraining in physical fitness centers

OBJECTIVE

The aim of this study was to evaluate the occurrence of the well-known predisposing factors and signs and symptoms usually associated with either overreaching or overtraining syndrome in physical fitness centers in São Paulo City, Brazil.

METHOD

A questionnaire consisting of 13 question groups pertaining to either predisposing factors (1-7) or signs and symptoms (8-13) was given to 413 subjects. The general training schedule of the volunteers was characterized by workout sessions of 2.18 ± 0.04 h for a total of 11.0 ± 0.3 h/week for 33 ± 2 months independent of the type of exercise performed (walking, running, spinning, bodybuilding and stretching). A mean score was calculated ranging from 1 (completely absent) to 5 (severe) for each question group. A low occurrence was considered to be a question group score lower than 4, which was observed in all 13 question groups.

RESULTS

The psychological evaluation by POMS Mood State Questionnaire indicated a normal non-inverted iceberg. The hematological parameters, creatine kinase activity, cortisol, total testosterone and free testosterone concentrations were within the normal ranges for the majority of the volunteers selected for this analysis (n = 60).

CONCLUSION

According to the questionnaire score analysis, no predisposing factors or signs and symptoms usually associated with either overreaching or overtraining were detected among the members of physical fitness centers in São Paulo City, Brazil. This observation was corroborated by the absence of any significant hematological or stress hormone level alterations in blood analyses of the majority of the selected volunteers (n = 60).

Inflammatory biomarkers increase with severity of upper-extremity overuse disorders

MSDs (musculoskeletal disorders) from overuse are common occupational health problems that cause pain, functional loss and loss of work time. The aim of the present study was to determine whether a relationship exists between the severity of early-onset overuse-related MSDs of the upper extremity and serum levels of IL-1beta (interleukin-1beta), TNF-alpha (tumour necrosis factor-alpha), IL-6 (interleukin-6) and CRP (C-reactive protein). Twenty-two subjects with upper-extremity MSDs due to overuse for no longer that 12 weeks were stratified according to the severity of upper-extremity signs and symptoms as determined by a UBMA (upper-body musculoskeletal assessment). Nine asymptomatic subjects also participated. Serum cytokines were analysed using ELISA, and CRP was analysed using a laser nephelometry technique. CRP was strongly correlated, and TNF-alpha, IL-1beta and IL-6 were moderately correlated, with UBMA scores. Only CRP and TNFalpha were significantly associated with UBMA scores in an ordinal logistic regression analysis in which age and BMI (body mass index) were covariates. These results are of clinical importance as they suggest that early-onset overuse-related MSDs may have an inflammatory component. The possibility of using a combination of serum biomarkers to follow the progression of overuse-related MSDs or their response to therapeutic intervention may be of interest to clinical practitioners and should be the focus of future research.

Monitoring for overreaching in rugby league players

The aim of this study was to identify indicators of non-functional overreaching (NFOR) in team sport athletes undertaking intensive training loads. Eighteen semi-professional rugby league players were randomly assigned into two pair matched groups. One group completed 6 weeks of normal training (NT) whilst the other group was deliberately overreached through intensified training (IT). Both groups then completed the same 7-day stepwise training load reduction taper. Multistage fitness test (MSFT) performance, VO2 (max), peak aerobic running velocity (V (max)), maximal heart rate, vertical jump, 10-s cycle sprint performance and body mass were measured pre- and post-training period and following the taper. Hormonal, haematological and immunological parameters were also measured pre-training and following weeks 2, 4 and 6 of training and post-taper. MANOVA for repeated measures with contrast analysis indicated that MSFT performance and VO2 (max) were significantly reduced in the IT group over time and condition, indicating that a state of overreaching was attained. However, the only biochemical measure that was significantly different between the IT and NT group was the glutamine to glutamate (Gln/Glu) ratio even though testosterone, testosterone to cortisol (T/C) ratio, plasma glutamate, and CK activity were significantly changed after training in both groups. Positive endurance and power performance changes were observed post-taper in the IT group confirming NFOR. These changes were associated with increases in the T/C ratio and the Gln/Glu ratio and decreases in plasma glutamate and CK activity. These results indicate that although there was no single reliable biochemical marker of NFOR in these athletes, the Gln/Glu ratio and MSFT test may be useful measures for monitoring responses to IT in team sport athletes.

The effect of eccentric exercise on position sense and joint reaction angle of the lower limbs

Impaired position sense and impaired joint reaction angle of the lower limbs after muscle-damaging activities is a serious functional limitation that may lead to an increased risk of injury, particularly in older populations. The purpose of the present study was to examine whether position sense and joint reaction angle to release can be affected by eccentric exercise-induced muscle damage. Twelve women underwent an isokinetic exercise session of the lower limb. Isometric peak torque, delayed-onset muscle soreness, serum creatine kinase, position sense, and knee joint reaction angle to release were examined before, immediately after, and 24, 48, and 72 h post-exercise. Due to the effect of eccentric exercise, subjects persistently placed their lower limb at a more extended position, representing a shorter knee extensor muscle. Eccentric exercise increased the knee reaction angle of the lower limb after release from 0 degrees and 15 degrees but not from 30 degrees and 45 degrees . Position sense and joint reaction to release were similarly affected by eccentric exercise and independently of visual feedback. Position sense was impaired only immediately post-exercise (probably due to muscle fatigue), whereas impairment of the reaction angle to release persisted up to 3 days post-exercise (probably due to muscle damage). Attenuation of position sense and joint reaction angle of the lower limbs after damaging activities is a serious functional limitation that may lead to an increase risk of injury, particularly in older populations.

Intensive exercise training suppresses testosterone during bed rest

Spaceflight and prolonged bed rest (BR) alter plasma hormone levels inconsistently. This may be due, in part, to prescription of heavy exercise as a countermeasure for ameliorating the adverse effects of disuse. The initial project was to assess exercise programs to maintain aerobic performance and leg strength during BR. The present study evaluates the effect of BR and the performance of the prescribed exercise countermeasures on plasma steroid levels. In a 30-day BR study of male subjects, the efficacy of isotonic (ITE, n = 7) or isokinetic exercise (IKE, n = 7) training was evaluated in contrast to no exercise ( n = 5). These exercise countermeasures protected aerobic performance and leg strength successfully. BR alone (no-exercise group) did not change steroidogenesis, as assessed by the plasma concentrations of cortisol, progesterone, aldosterone, and free (FT) and total testosterone (TT). In the exercise groups, both FT and TT were decreased ( P < 0.05): FT during IKE from 24 ± 1.7 to 18 ± 2.0 pg/ml and during ITE from 21 ± 1.5 to 18 ± 1 pg/ml, and TT during IKE from 748 ± 68 to 534 ± 46 ng/dl and during ITE from 565 ± 36 to 496 ± 38 ng/dl. The effect of intensive exercise countermeasures on plasma testosterone was not associated with indexes of overtraining. The reduction in plasma testosterone associated with both the IKE and ITE countermeasures during BR supports our hypothesis that intensive exercise countermeasures may, in part, contribute to changes in plasma steroid concentrations during spaceflight.

Pure eccentric exercise does not activate blood coagulation

Eccentric exercise can cause skeletal muscle damage with ultrastructural disruption, inflammation and increased proteolytic enzyme activity. It may be possible that these changes are able to trigger blood coagulation in vivo. The aim of the study was to investigate changes in blood coagulation via the measurement of aPTT, the thrombin potential (total [TTP] and endogenous [ETP], both intrinsic [in] and extrinsic [ex]) and the thrombin generation (prothrombinfragment 1 + 2 [F1 + 2] and thrombin-antithrombin complex [TAT]) after pure eccentric exercise. Seventeen healthy non-smokers (28 +/- 6 years, VO2-peak 59 +/- 7 ml/min/kg) underwent pure eccentric down jumps (9 x 28 isolated down jumps in 90 min, drop from a height of 55 cm), a cycle exercise (90% of the individual anaerobic threshold for 60-90 min) and a control experiment on different days. Blood samples were drawn after a 30-min rest, immediately, and 2 h after exercise. After the cycle exercise, a clear shortening by 12% (P<0.001) in aPTT and an increase in TTPin (13%; P<0.05) and TAT (33%; P<0.05) in comparison to the control experiment were seen, while after eccentric exercise only minimal changes in aPTT and thrombin potential (TTPin, ETPin) and no thrombin generation (F1 + 2 and TAT) were found. In contrast to concentric dynamic exercise, e.g. cycle ergometry, only insignificant changes in thrombin potential and no thrombin generation could be observed after skeletal muscle damage induced by pure eccentric exercise. It can be concluded that the mechanical impact associated with eccentric exercise does not activate blood coagulation.

Hemorheological correlates of fitness and unfitness in athletes: moving beyond the apparent "paradox of hematocrit"?

Negative correlations between blood viscosity parameters and fitness have been reported, but their physiological meaning remains incompletely understood. Since rheo-active treatments are used in athletes doping, we aimed at clarifying the relationships between hematocrit (Hct), viscosity and performance by comparing aerobic capacity, overtraining questionnaire, and hemorheological parameters.

SUBJECTS AND METHODS

29 sportsmen (24.71+/-1.05 yr; 74.90+/-1.44 kg; 178.5+/-1.05 cm) underwent a standardised exercise test. Physical working capacity (W170), maximal power output (Wmax) and maximal oxygen consumption (VO2max ) were calculated. Viscometric measurements were done with a MT 90 Medicatest viscosimeter. Hct was measured with microcentrifuge. All subjects answered the overtraining questionnaire proposed by the French Society for Sports Medicine.

RESULTS

The best correlate of maximal power output (Wmax) was whole blood viscosity (r=-0.383, p<0.001). The stepwise regression analysis only selected Hct as W170 determinant (r=-0.66, p<0.001). Similarly the best determinant of VO2max, expressed as a percentage of theoretical values, was Hct (r=-0.462, p=0.01). Hct/viscosity ratio (Hct/eta), a proposed index of Hct's positive influence on O2 transfer to tissues, was positively correlated to Wmax expressed as a percentage of theoretical values (r=0.487, p=0.02). The overtraining score was correlated to plasma viscosity (r=0.450, p=0.016).

CONCLUSION

The best hemorheogical correlate of fitness is a low hematocrit and the best hemorheological correlate of overtraining is increased plasma viscosity.

High level of plasma thrombomodulin (TM) concentration and correlation with endothelin (ET)-1 in vibration-exposed patients

We measured plasma level of TM and ET-1 in vibration exposed patients. The results showed the plasma level of TM in vibration exposed patients was significantly higher than in normal controls. The present findings showed relatively wide damage of endothelial cells in the vascular bed of vibration-exposed patients. On the other hand, the mean level of ET-1 in these patients tended to be higher than in normal controls, though there was no difference. Further studies are necessary about the mechanism of endothelial damage in vibration syndrome patients and its contribution to peripheral circulatory disturbance of vibration syndrome including the role of ET-1.