Typical normal-service engine valve-train components may be too lightweight for operating at high revolutions per minute (RPM), leading to valve float.  This occurs when the action of the valve no longer completely opens or closes, such as when the valve spring force is insufficient to close the valve (it does not fully rest on its seat even though the cam would allow the valve to close) causing a loss of control of the valvetrain, as well as a drop in power output.  Valve float will damage the valvetrain over time, and could cause the valve to be damaged as it is still partially open while the piston comes to the top of its stroke.  Upgrading to high pressure valve springs could allow higher valvetrain speeds, but this would also overload the valvetrain components and cause excessive and costly wear. 
Treatment of hypogonadal men with Sustanon 250 results in a clinically significant rise of plasma concentrations of testosterone, dihydrotestosterone, estradiol and androstenedione, as well as decrease of SHBG (Sex hormone binding globulin). Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are restored to the normal range. In hypogonadal men, treatment with Sustanon 250 results in an improvement of testosterone deficiency symptoms. Moreover, treatment increases bone mineral density and lean body mass, and decreases body fat mass. Treatment also improves sexual function, including libido and erectile function. Treatment decreases serum LDL-C, HDL-C and triglycerides and increases haemoglobin and haematocrit, which may lead to polycythaemia. No clinically relevant changes in liver enzymes and PSA have been reported. Testosterone also produces systemic effects, such as increasing the retention of sodium, potassium and chloride leading to an increase in water retention. Treatment may result in an increase in prostate size, and worsening of lower urinary tract symptoms, but no adverse effects on prostate symptoms have been observed. In hypogonadal diabeteic patients, improvement of insulinsensitivity and/or reduction in blood glucose have been reported with the use of androgens. In boys with constitutional delay of growth and puberty, treatment with Sustanon 250 accelerates growth and induces development of secondary sex characteristics. In female-to-male transsexuals, treatment with Sustanon 250 induces masculinisation.