Online registration may not be allowed for all activities. To enroll into a group exercise class, please reserve your spot via our mobile app [https://ymcagbw.org/mobileapp#faq-question-949250480]. Please contact us during regular business hours for registration information. Les Mills CORE is a 30-minute workout, designed to tone your body, improve your core strength and aid with injury prevention. Category Group Exercise Location Mind/Body Studio at Lionville Branch Instructor Desiree Monsilovich