Overload- Overload states that a muscle or muscle group must work harder than normal to achieve gains. The amount of training you undertake must be more than you are accustomed to.
Tips- I don't like to use the words “ No Pain No Gain” but slight discomfort is expected. I love when my muscles are talking to me . Listen to your body there is a such thing as good pain and bad pain and the more intune with your body you are you will know the difference between the two.  Slight quivering while doing weights is considered good pain or overload- for cardio you want to break a sweat. Remember in order for that muscle to become bigger and stronger it has to work against a heavier load than normal.

Progression- You need to increase your workout levels enough to see results, but not so much that you increase your risk of injury. Once that exercise becomes easy whether its resistance training or cardio training you need to increase the intensity.
Tips - Use the “10 percent rule” increase your exercise Frequency, Intensity and Time by no more than 10 percent per week- FIT PRINCIPLES
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Specificity- The principle of specificity states that training should closely match the action or activity that you wish to improve. . You would never expect to run a mile well by only working your upper body, nor would you expect to  gain muscle in your biceps by just doing squats.
Tips. If you are training to run a mile start by walking, jogging then running. Your main focus should be to primalily train the muscles used for running (legs and heart)

Remember your body will adapt to the demands you place on it you just have to convince the mind.

Reversibility- Use it or lose- Fitness cannot be stored. D-time training only takes 2 weeks to start losing your hard earned fitness gains. Most of your improvements  could be GONE in a couple of months. The good news is if you have been working out for years you will gain it back faster than someone who is new to exercise.
Tips- You can reduce the number of exercise sessions a week and cut time if you increase intensity. Look to do moderate to vigorous- intensity exercises or try HIIT Training - High Intensity Interval Training= High intensity exercises with recovery periods of lower intensity exercises.  (this is not recommended for the newbie)

Individuality- Adaptation to training overload may vary significantly from person to person. Two people who are doing the same exercise programs may have completely different responses.
A person who responds to exercise is a responder and a person who does not respond as well is a non- responder.
Tips - If you are a non- responder to exercise you may have to work a bit harder or increase the intensity as a non responder myself I need a longer warm up. Once I have completed the longer warm up I am able to go longer and harder. Not all is fair in love and exercise!!!

Recuperation- Rest and Recovery

ery is crucial in resistance training. What people don't know that are new to exercise is that most training adaptations take place during the rest period. Rest periods will vary depending on how hard a person has been training. For most resistance training a 24-48 rest period is sufficient for the muscle groups stressed/worked.

Tips-  Listen to your body- If you are starting to feel more fatigued or more muscle soreness than usual than give your body a rest and let those muscles repair themselves.