Strive 4 Strength is designed to emulate the comfort of at-home workouts with toiletries, a steam room, towels, and no daunting crowds. In the boutique, the staff responsible for personal training and fitness classes works to set every visitor at ease. Drumrolls of feet on the floor drift from boot-camp classes, which get hearts thundering with squats, shoulder presses, and jumping jacks. Vinyasa yoga, on the other hand, teaches slow, breath-paired postures designed to bolster flexibility and relaxation. In cardio rooms, iPod-compatible treadmills and elliptical units whirr, tracking speed, distance, and how many lyrics to “Eye of the Tiger” you know. Expresso bikes pit exercisers against online opponents, and free weights build dense knots of muscle with a clattering din.