thyroid

overactive can cause quad weakness not sure bout under active :?

Need to look for many muscle imbalances. Thyroid issues usually end up creating problems with the rotator cuff muscles and brings about shoulder problems, irrelevant of hyer or hypo. Need to look at metabolic issues. Hypo will often be tyrosine or iodine deficient which can create issues in itself. Often people who are hypo and iodine deficient will have Vitamin A issues or omega 3/6 ratio issues that result in fatigue on both aerobic and anaerobic exertion.

Crohn's is a bit more of an issue. Thyroid stuff can be dealt with. These people will have absorption issues due to intestinal scarring. (if severe enough) Will especially link to dehydration. Will often have TFL or hamstring issues to a lesser extent. This can create lateral knee problems in rare circumstances.
People with Chron's need to get away from ALL stimulants. Including all refined sugars (fructose is ok - fruit sugar), caffiene and carbonated drinks. This includes sports drinks unless you have done in excess of at least an hours training at the moment of drinking. (the body breakls down glucose differently after this time). In addition you need to stay away from Nightshade veggies (such as tomato, potato, egg plant, capsicum) and try and remove lectins (found in grains) from your diet. Given that you will need the carbs for sport this becomes difficult. Thus stay away from wheat and shift to either Rye or Millet grains as they don't seem to create the same level of immune response as the lectins found in wheat.