Amphetamine and secobarbital were compared with a placebo as to their effects on 57 college athletes. Performance was measured objectively. Subjective estimates of performance and mood were also obtained. Performance was significantly improved by 14 mg. of amphetamine sulfate, significantly impaired by 100 mg. of secobarbital, and not significantly influenced by 50 mg. of secobarbital. Subjects reported that amphetamine stimulated them, improved coordination and form, increased strength and endurance, and increased feelings of mental and physical activation, boldness, elation, and friendliness. The 100-mg. dose of secobarbital produced intoxication, elation, "deactivation," and distortion in judgment; the 50-mg. dose produced elation and activation.
Smith GM, Beecher HK. AMPHETAMINE, SECOBARBITAL, AND ATHLETIC PERFORMANCEII. SUBJECTIVE EVALUATIONS OF PERFORMANCES, MOOD STATES, AND PHYSICAL STATES. JAMA. 1960;172(14):1502–1514. doi:10.1001/jama.1960.03020140038009