Physical training effects in renal transplant recipients.

INTRODUCTION: Several studies demonstrated the benefits of rehabilitation in uraemic patients. This study evaluates physical and psychosocial effects of exercise on renal transplant recipients (RTRs). PATIENTS AND METHODS: Eight RTRs were evaluated before and after an exercise training consisting of thirty 40-minute sessions, three times a week, performed with the interval training technique. RESULTS: Hospital Anxiety and Depression Scale (HADS) significantly decreased (p<0.04 and <0.008, respectively). Quality of life mean scores (SF-36 test) significantly increased (p<0.000). No differences were recorded for muscle and fat mass, maximal explosive power of the lower limbs, alkaline and acid phosphatase, parathormone (PTH), myoglobin, lipoprotein-A, glomerular filtration rate (GFR), at rest heart rate, and cardiac troponin. IL-6 decreased from 2.8±0.6 to 1.7±0.5 pg/mL (p<0.01). Resting MAP fell from 112±4 to 99±3 mmHg (p<0.02). The metabolic threshold rose from 33±4 to 43±5% (p<0.033). The blood lactate level at peak exercise increased from 5.2±0.9 to 6.2±0.7 mmol/L (p<0.012). The maximum oxygen uptake increased from 1200±210 to 1359±202 mL/min (p<0.05), iso-load oxygen uptake decreased from 1110±190 to 1007±187 mL/min (p<0.034). The maximum working capacity increased from 90±14 to 115±15 watts (p<0.000). CONCLUSION: This study suggests that an appropriate dose of physical training is a useful, safe and non-pharmacologic contribution to RTR treatment.

Body composition and muscular strength changes after moderate activity: association with matrix metalloproteinase polymorphisms.

Remodeling of skeletal muscles is regulated by matrix metalloproteinases (MMPs). Functional genetic polymorphism (PM), modulating the expression of some MMPs, might be associated to different body composition and muscular strength improvement after exercise. Genetic PM of MMP-1 (G+/- at -1607), MMP-3 (5A/6A at -1171) and MMP-9 (Cytosine-Adenine microsatellite=(13-27)CA) repeats, around -90), body cell mass (BCM), extracellular water (ECW) and isometric maximal extensor strength (MES) of both legs were determined in 17 old sedentary women at the beginning and at the end of a 24 week physical exercise program. A 12 and 72% increase in BCM and MES, respectively, and 11% reduction in ECW were observed at the end of the program. Carriers of G-insertion in MMP-1, PM increased their BCM (7 kg vs. -1.5, p=0.007) and lost ECW (9% of total body water vs. 0.1%, p=0.004) more than the non-carriers; homozygote for 21 or less CA repeats/allele in MMP-9 PM gained more MES (115 N, interquartile range=IQR=63-132) than carriers of longer microsatellites (63 N, IQR=40-86, p=0.028). MMP-3 did not show any association with body composition and exercise-related strength changes. Exercise in elderly women increases BCM and strength, these changes are associate to specific MMP genotypes.

Influence of the contact time on coupling time and a simple method to measure coupling time.

The enhancement of performance in stretch shortening cycle (SSC) exercises has been attributed to the recoil of elastic energy stored during the stretching phase and depends on the duration of the coupling time (T(coupling)) i.e., the duration of the isometric phase occurring between the stretch and the shortening of the muscle. However, instead of T(coupling), the contact time (T(contact))--i.e., the sum of T(coupling) plus the duration of the stretching and shortening phases that precede and follow T(coupling)--is more easily and often measured. The aim of this study was to investigate the T(coupling) changes within a large range of T(contact), in order to propose a possible relationship between T(coupling) and T(contact), thus allowing the accurate measurement of T(coupling )only from a tachometer and force data obtained classically in vertical jumps, jumps on sledge apparatus and running on force treadmills. Eleven subjects performed SSC exercises on a sledge apparatus with a large range of T(contact) (400, 700, 1,000, 1,500, 2,000 and 2,500 ms). The T(coupling) and T(contact) values were measured individually, from force platform recordings and the velocity of the carriage seat obtained by a tachometer. For the longest T(contact) (i.e., from 850 to 2,500 ms), we observed a significant linear relationship between T(contact) and T(coupling). This transition between T(contact) shorter or longer than about 850 ms seems to be important and to correspond to T(coupling) close to 300 ms. This limit observed in the present study could be explained physiologically due to a possible modification of the cross-bridges formation.