For the first 15 minutes of my tai chi class, we remain entirely in one spot to warm up. From afar, it probably looks as though we’re standing with our arms by our side and then – in slow motion – lifting them in front of us to 90 degrees. But if you were to look inside my brain, you would see my synapses firing trying to keep up with the instructor’s directions to do things that can’t be seen. “Form the arches under your feet. Soften your knees, not bending,” says Angela, a tai chi instructor of 28 years. “Visualise the back of your knees. Relax there to relax your knee bones in front.” I realise I rarely direct thoughts to my knees (there hasn’t been much knee-d to before this), but again, before there’s time to dwell, there’s more to do. According to Angela, a successful hour of tai chi is an hour with no negative thoughts. “If your mind and body go together,” she says. “That’s all that matters.” ‘It turns out …