High-Force Versus Low-Force Lumbar Traction in Acute Lumbar Sciatica Due to Disc Herniation: A Preliminary Randomized Trial.

OBJECTIVE: This study compared the effects of high-force versus low-force lumbar traction in the treatment of acute lumbar sciatica secondary to disc herniation. METHODS: A randomized double blind trial was performed, and 17 subjects with acute lumbar sciatica secondary to disc herniation were assigned to high-force traction at 50% body weight (BW; LT50, n = 8) or low force traction at 10% BW (LT10, n = 9) for 10 sessions in 2 weeks. Radicular pain (visual analogue scale [VAS]), lumbo-pelvic-hip complex motion (finger-to-toe test), lumbar-spine mobility (Schöber-Macrae test), nerve root compression (straight-leg-raising test), disability (EIFEL score), drug consumption, and overall evaluation of each patient were measured at days 0, 7, 1, 4, and 28. RESULTS: Significant (P < .05) improvements were observed in the LT50 and LT10 groups, respectively, between day 0 and day 14 (end of treatment) for VAS (-44% and -36%), EIFEL score (-43% and -28%) and overall patient evaluation (+3.1 and +2.0 points). At that time, LT50 specifically improved in the finger-to-toe test (-42%), the straight-leg-raising test (+58), and drug consumption (-50%). No significant interaction effect (group-by-time) was revealed, and the effect of traction treatment was independent of the level of medication. During the 2-week follow-up at day 28, only the LT10 group improved (P < .05) in VAS (-52%) and EIFEL scores (-46%). During this period, no interaction effect (group-by-time) was identified, and the observed responses were independent of the level of medication. CONCLUSIONS: For this preliminary study, patients with acute lumbar sciatica secondary to disc herniation who received 2 weeks of lumbar traction reported reduced radicular pain and functional impairment and improved well-being regardless of the traction force group to which they were assigned. The effects of the traction treatment were independent of the initial level of medication and appeared to be maintained at the 2-week follow-up.

Effect of eccentric versus concentric exercise training on mitochondrial function.

INTRODUCTION: The effect of eccentric (ECC) versus concentric (CON) training on metabolic properties in skeletal muscle is understood poorly. We determined the responses in oxidative capacity and mitochondrial H2 O2 production after eccentric (ECC) versus concentric (CON) training performed at similar mechanical power. METHODS: Forty-eight rats performed 5- or 20-day eccentric (ECC) or concentric (CON) training programs. Mitochondrial respiration, H2 O2 production, citrate synthase activity (CS), and skeletal muscle damage were assessed in gastrocnemius (GAS), soleus (SOL) and vastus intermedius (VI) muscles. RESULTS: Maximal mitochondrial respiration improved only after 20 days of concentric (CON) training in GAS and SOL. H2 O2 production increased specifically after 20 days of eccentric ECC training in VI. Skeletal muscle damage occurred transiently in VI after 5 days of ECC training. CONCLUSIONS: Twenty days of ECC versus CON training performed at similar mechanical power output do not increase skeletal muscle oxidative capacities, but it elevates mitochondrial H2 O2 production in VI, presumably linked to transient muscle damage.

Intramuscular pressure before and after botulinum toxin in chronic exertional compartment syndrome of the leg: a preliminary study.

BACKGROUND: Botulinum toxin A (BoNT-A) is used in the treatment of muscle hypertrophy but has never been used in chronic exertional compartment syndrome (CECS). The objective diagnostic criterion in this condition is an abnormally elevated intramuscular pressure (IMP) in the compartment. In this study, the IMP was measured 1 minute (P1) and 5 minutes (P5) after the exercise was stopped before and after BoNT-A injection. HYPOTHESIS: Botulinum toxin A reduces the IMP (P1 and P5) and eliminates the pain associated with CECS. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Botulinum toxin A was injected into the muscles of moderately trained patients with an anterior or anterolateral exertional compartment syndrome of the leg. The BoNT-A dose (mean ± SD) ranged from 76 ± 7 to 108 ± 10 U per muscle, depending on which of the 5 muscles in the 2 compartments were injected. The primary end point was IMP (P1, P5). Secondary end points were exertional pain, muscle strength, and safety. Follow-up was conducted up to 9 months. RESULTS: A total of 25 anterior compartments and 17 lateral compartments were injected in 16 patients. The time interval (mean ± SD) between the BoNT-A injection and after BoNT-A injection IMP measurement was 4.4 ± 1.6 months (range, 3-9 months). In the anterior compartment, P1 and P5 fell by 63% ± 17% (P < .00001) and 59% ± 24% (P < .0001), respectively; in the lateral compartment, P1 and P5 fell by 68% ± 21% (P < .001) and 63% ± 21% (P < .01), respectively. Exertional pain and muscle strength were monitored, based on the Medical Research Council score. The exertional pain was completely eliminated in 15 patients (94%). In 5 patients (31%), the strength of the injected muscles remained normal. In 11 patients (69%), strength decreased from 4.5 (out of 5) to 3.5 (P < .01), although without functional consequences. In the conditions of this study, BoNT-A showed a good safety profile in patients with CECS. CONCLUSION: In this case series, BoNT-A reduced the IMP and eliminated exertional pain in anterior or anterolateral CECS of the leg for up to 9 months after the intervention. The mode of action of BoNT-A is still unclear. A randomized controlled study should be carried out to determine whether BoNT-A can be used as a medical alternative to surgical treatment.

Eccentric exercise training: modalities, applications and perspectives.

Eccentric (ECC) exercise is classically used to improve muscle strength and power in healthy subjects and athletes. Due to its specific physiological and mechanical properties, there is an increasing interest in employing ECC muscle work for rehabilitation and clinical purposes. Nowadays, ECC muscle actions can be generated using various exercise modalities that target small or large muscle masses with minimal or no muscle damage or pain. The most interesting feature of ECC muscle actions is to combine high muscle force with a low energy cost (typically 4- to 5-times lower than concentric muscle work) when measured during leg cycle ergometry at a similar mechanical power output. Therefore, if caution is taken to minimize the occurrence of muscle damage, ECC muscle exercise can be proposed not only to athletes and healthy subjects, but also to individuals with moderately to severely limited exercise capacity, with the ultimate goal being to improve their functional capacity and quality of life. The first part of this review article describes the available exercise modalities to generate ECC muscle work, including strength and conditioning exercises using the body's weight and/or additional external loads, classical isotonic or isokinetic exercises and, in addition, the oldest and newest specifically designed ECC ergometers. The second part highlights the physiological and mechanical properties of ECC muscle actions, such as the well-known higher muscle force-generating capacity and also the often overlooked specific cardiovascular and metabolic responses. This point is particularly emphasized by comparing ECC and concentric muscle work performed at similar mechanical (i.e., cycling mechanical power) or metabolic power (i.e., oxygen uptake, VO2). In particular, at a similar mechanical power, ECC muscle work induces lower metabolic and cardiovascular responses than concentric muscle work. However, when both exercise modes are performed at a similar level of VO2, a greater cardiovascular stress is observed during ECC muscle work. This observation underlines the need of cautious interpretation of the heart rate values for training load management because the same training heart rate actually elicits a lower VO2 in ECC muscle work than in concentric muscle work. The last part of this article reviews the documented applications of ECC exercise training and, when possible, presents information on single-joint movement training and cycling or running training programs, respectively. The available knowledge is then summarized according to the specific training objectives including performance improvement for healthy subjects and athletes, and prevention of and/or rehabilitation after injury. The final part of the article also details the current knowledge on the effects of ECC exercise training in elderly populations and in patients with chronic cardiac, respiratory, metabolic or neurological disease, as well as cancer. In conclusion, ECC exercise is a promising training modality with many different domains of application. However, more research work is needed to better understand how the neuromuscular system adapts to ECC exercise training in order to optimize and better individualize future ECC training strategies.