Exercise performance indices in normal and anabolic steroid treated trotters

Abstract

SummarySix adult Finnhorse trotters performed a standardised exercise test (SET) on a treadmill and a 4000 m maximal exercise test (MET) on a racetrack before, immediately and 13 weeks after a 14 week treatment with nandrolone laurate. Six other trotters served as contrculs. All horses were trained during the whole experiment. Blood lactate concentration, VZo0, VLa4 and red cell volume (CV) were determined in connection to the SET and blood lactate concentration, heart rate and performance time in the MET. All horses significantly improved their performance in the MET, but no differences were observed between the 2 groups. Nandrolone treatment caused a significant (Pe0.05) increase in the CV and in the percentage of the oxidative type ZZA fibres in the middle gluteal muscle. During the experiment VZOO and V L~~ did not change (-0.05) in either of the groups. The results indicate that CV was the only variable that predicted performance during the last lo00 m of the maximal test, whereas indicators of aerobic capacity, like VZM and V L~~, were of minor value. In the control group, the increase in the blood lactate concentration in the SET correlated positively with the total performance time (r:=635; P<O.Ol) and the time of the last 1000 m (r=0.727; P<O.OOl) in the MET, but no correlation was found in the nandrolone group. The differences between the control and nandrolone groups suggest that both aerobic and anaerobic energy production in muscle are affected by nandrolone treatment.have been demonstrated in the fast twitch fibres (Saborido et Celotti and Negri Cesi 1992), whereas decreases in the volume density of mitochondria has been found in the slow twitch muscle (Soares and Duerte 1991). Recently it was shown that rabbit muscles fibialis anterior (TA) and extensor digitomm longus (EDL), which are located subjacent to each other and have similar fibre type composition, respond differently to anabolic steroid treatment (Salmons 1992). Hypertrophy and decrease in the oxidative capacity were seen in the TA, but responses were not detected in the EDL. This study implies, that the effects of anabolic steroids are also muscle specific.Studies on the effects of anabolic steroids in horses have not been able to demonstrate any synergistic effects with training or improvement in racing performance (Snow et al. 1982b;Thornton et al. 1991). The percentage of fast twitch oxidative fibres decreased in the middle gluteal muscle of nandrolone treated geldings at rest (Snow et al. 1982a) and the responses of the muscle fibre composition to training were similar in the control and anabolic steroid treated geldings (Nimmo et al. 1982). The combination of training and anabolic steroids, but not training alone, caused a significant inceases in the activities of 2 mitochondrial enzymes, citrate synthase and R-hydroxyacyl CoA dehydrogenase, suggesting an increase in the oxidative capacity (Nimmo et al. 1982). Effects of anabolic steroids on the aerobic performance indices have not been studied in adult horses and, therefore, the a...

Effects of Nandrolone Treatment on Recovery in Horses After Strenuous Physical Exercise

“…The short nandrolone treatment used here did not increase CV, thus oxygen-carrying capacity remained unaffected. This ®nding differs from an earlier study, in which Hyyppa È et al (1995) reported a signi®cant increase in CV after 14-week nandrolone treatment, although equal plasma nandrolone concentrations were achieved. This suggests that long treatments with anabolic steroids are needed before erythropoiesis is increased.…”

“…In mares and geldings, a 14‐week treatment with nandrolone laurate increases red cell volume, makes the horses more aggressive, and increases the percentage of type IIA fibres and the cross‐sectional area of type I fibres (Hyyppä et al., 1995; Hyyppä et al., 1997a). Despite these behavioural and other changes, no controlled studies on horses yet exist to show whether anabolic steroids improve physical performance in comparison with that of similarly trained control horses, and at least three studies demonstrate that anabolic steroids offer no beneficial effect on exercise performance (Snow et al., 1982; Thornton et al., 1991; Hyyppä et al., 1995). Alway and Starkweather (1993) have suggested that anabolic steroids may improve adaptation to physical exercise, and therefore enhance the ability of an individual to tolerate increased intensity of training more than would otherwise be possible.…”

Androgen Receptors and Skeletal Muscle Composition in Trotters Treated with Nandrolone Laureate

“…3). In the AS group, but not in the C group, the AR concentration at the end of nandrolone treatment correlated positively with percentage of type IIA fibres (r =0.933, P < 0.05; fibre type values taken from HyyppA et al, 1995).…”

“…Androgenic, anabolic steroids (AS), synthetic derivatives of testosterone, have been widely used to improve physical performance, although this is scientifically controversial (CELOTfl and NEGRI CBSI, 1992;SNOW, 1993). In controlledstudies, administration of AS to horses has failed to improve performance capacity (SNOW et al, 1982b;THORNTON et al, 1991;HyyppA et al, 1995), whereas other anabolic effects have been observed, such as increases in erythropoiesis and nitrogen retention (SNOW et al, 1982b;NIMMO et al, 1982;HyyppA et al, 1995).…”

A review of designer anabolic steroids in equine sports

“…In contrast to the well‐documented advantages that anabolic steroids offer to human athletes, the effects of anabolic steroids in equine competitors are not well‐established . A study has shown that short‐term nandrolone (17β‐hydroxyestr‐4‐en‐3‐one) administration increased the glycogen content of post‐exercise muscle tissue; however, this is in contrast with two studies that found no observable changes resulting from nandrolone administration . It has been shown that steroid administration delayed closure of epiphyseal growth plates in Standardbreds, and suggested that this could lead to a potential increase to the long‐term risks of injury during training .…”