When she was 14 and a competitive equestrian, the Swedish designer Ellen Hodakova Larsson, who has made a name for herself by spinning old stuff into fashion gold, attended a training camp. There, she was paired with a horse larger and more volatile than any she’d encountered before. The stallion, she recalled, seemed able to jump twice his considerable height into the air. Rather than unnerving—or, let’s be honest, terrifying—her, the experience taught the young rider to trust herself. “I told myself, ‘Never be afraid of this,’ ” says Larsson, now 32. “If you keep calm and are stable in yourself, you will find that the world is not as horrific as it can seem to be.” In her chosen career, the lesson has proven invaluable.
In September, Larsson, who…