Ключевые слова: 20s, ache, aching, adult, african, alone, arthritis, background, bad, body, city, cramp, cramping, difficulties, discomfort, exhaustion, fitness, hurt, hurting, joint, joints, legs, looking, male, man, men, natural, one, osteoporosis, outside, pain, painful, people, person, pressure, running, sore, spasm, sport, sports, sports injury, sprain, standing, stiff, strain, stress, tense, tension, urban, young,