People may lose muscle mass as they age, but resistance training can slow the onset of this condition or even reverse it, experts say. The number of centres offering an evidence-based strength-training programme which aims to improve the functional abilities of the elderly is on the rise. Four more of such centres will open this year, taking the total number to 33 by the end of the year. Thirteen of the centres are now open to the public. The rest are eldercare facilities and nursing homes, which offer the programme to their residents. There is already a waiting list for the 12-week programme known as Gym Tonic, which is carried out by trained therapists using high-tech, air-powered equipment from Finland that is gentler on the joints. Around 4,000 seniors have gone on the programme since the Lien Foundation brought it to Singapore in 2015 and opened it to the public in 2017, it said. The 12-week programme costs $150 to $240, depending on the centre. There are 400 people on the wait list at the Bishan Community Club Gym Tonic centre, which opened to the public in April last year.