Yes, with supervision from an adult. Especially a good idea for a 14 yr old to go to the gym, if they are an athlete. A 14 year old should go to the gym with adult supervision, or with help from a personal trainer. Many gyms don't allow anyone under age 16 to workout without being acccompanied by an adult.
Can a 14 year old do workout?
But when it comes to 14-year-olds interested in weight training, it's reasonable to question whether strength training is safe and how to get started. The good news is that most teens can participate in a fitness program that includes resistance training, cardiovascular exercise, and competitive or recreational sports.17 abr 2019
How old do you have to be to go to Planet Fitness without a membership?
Membership is open to anyone 13 years or older. Members ages 13 and 14 must be accompanied by their parent or guardian at all times.