I woke this fine Saturday morn with more than I'd bargained. What I'd bargained for was a few tight muscles - a little in the legs, a little in the butt, a little in the arms. U u - allll over muscle ache. Calves, hips, tiny muscles in places I didn't know I had muscles - I can feel them all... and I blame it on my gorgeously fit but supremely strict taskmaster of a sister.

She's a personal trainer, you see, and after having done Pilates for a decade or so she's taken a job as an instructor at the Heartcore Pilates studio in West Hampstead. Now I've done basic floor based pilates classes before and found them challenging. But this class was intense. And so it should be given my ‘quite average' core strength. I'll be working on it now, that's for sure because even though I'm bit tight and weary this morn I feel surprisingly upright, somewhat more steady when I move and of course ultra-aware of my body's every movement.

Pilates is a physical fitness system based on yoga and aerobic exercises that was created by the German Joseph Pilates during the first world war as a means to rehabilitate returning veterans. Joseph believed that both mental and physical health are crucial to one another and so created the Pilates system to work the entire body - strengthening, stretching, and stabilizing key muscles through proper alignment, centering, concentration, control, precision, breathing, and flowing movement.

I've never had back problems but most of my family has, my dad and sister in particular. Both rate it very highly. When I practiced the easier floor exercises all those years back I hadn't realised how weak my core muscles were and how tight my back was. When I missed a few sessions I noticed the difference in so much as my frame slumped a little, my spine felt less flexible and I'd get lazy lifting things by not bending and moving in the most body friendly was.

Time to get back to it I think! Not so sure about sister Brooke's ‘work to fatigue' philosophy - that one's going to get some getting use to.