This is Yoga ... the legs, grounding the fingers into the mat. Stepping the right leg forward, arms in line with the legs, straightening the front leg, just start to move into Triangle Pose.
Yoga can benefit anybody at any fitness level and at any age. Here's a great way to start. As you come to your yoga mat, put your hands on the floor and take table pose. You can start to warm up here.
Colder weather can indeed cause joint pain, especially in people with arthritis or other joint conditions. As temperatures drop, muscles and joints tend to stiffen because of reduced blood flow ...