What are the current recommendation for physical activity for adults?
The minimum recommendations for physical activity according to the American Heart Association and the American College of Sports Medicine are as follows; 150 minutes per week of moderate intensity physical activity or 75 minutes of vigorous intensity. It is recommended that 30 minutes of moderate or 20 minutes of vigorous should be performed on most, if not all day of the week. The 30 minutes can be split up into bouts throughout the day of 10 minutes or more. Additionally, there should be two days per week of some form of muscle strengthening or resistance exercise.
How does an individual lose fat mass while maintaining lean mass?
Body management largely comes down to energy balance or energy in vs energy out. Energy coming in is contained within the food and drinks we consume. Energy out or expended can come from a variety of areas such as physical activity, thermogenesis of food (energy required to absorb or digest different foods), and our basal metabolism (the energy required for our body to function). To lose weight (and fat) over time, energy going out should be more than energy coming in, AKA a negative energy balance. A good, realistic goal is to start by decreasing calories by 500 below your estimated energy needs each day to shoot for about 1 pound of weight loss per week. If you do not want much of this weight to come from lean mass (muscle and bone), then the individual should exercise and consume adequate protein.
What are the primary ways that joints in the body are classified? What are some examples of each?
Joints in the human body are classified in two different manners. The first is by structure. Fibrous joints are when two bones are connected directly together. Cartilaginous joints are when bones are joined by cartilage instead of direct connection. While bones in a synovial joint are not attached but instead are located within a joint capsule. The second way to classify joints is by the amount of movement allow. Synarthrosis joints are incapable of movement, and are typically fibrous in structure. An example would be in the cranial bones, where suture joints are formed by two plate bones fused together and little movement is allowed. Amphiarthrosis joints allow a small amount of movement and are typically cartilaginous in structure. The cartilage between them allows some flexibility and movement for shock absorption for joints like the sternum and the vertebrae. Diarthrosis joints are freely movable as they are typically synovial in strucure. Because the bones are not connected, but instead reside in a joint capsule surrounded by synovial fluid, they have freedom to move in multiple directions. These joints are the typical "movement" joints in the body such as the shoulder, knee, hip, etc...