Thermal clothing. If you cannot afford that try wearing something with fur underneath it or a thick wool coat, hoodie, jumper. Use multiple layers if in below zero conditions. Make sure your clothes are insulated to prevent any cold from reaching your chest so you don’t catch a cold or risk damaging your vital organs in the event you do suffer from hypothermia. You should definitely be wearing long pants that are insulated and spacious. You can wear undergarments like skins that are tight around the skin to preserve body heat and you should be wearing thick gloves. Beanies or wool/sheepskin any thick warm materials to put in your head. Last wear some thick socks with boots that are thick around the ankle to leg to prevent any snow/ ice/ cold water from reaching your legs
When you flex your muscles you are contracting them. When your muscle fibers gain tension through Actin and Myosin crossbridge cycling they may shorten due to the tension. This is called muscle contraction
