As we close out the month of May there's a strong chance we are becoming more active outside. I have on more occasions than I can count heard people talk about how they only go to the gym after the spring/summer season has ended. While your programming could and in some cases should be changed, it is unlikely that it should stop or pause. It is a common notion to believe that exercise is exercise. However, this is NOT true. Let me explain.
Let's say you like to garden and do yard work. You work up a good sweat and at times even find yourself a little breathless from the activity. This is a great thing, as this means the heart is working harder and this work will result in improved cardiovascular fitness. Some of the muscles might even get worked hard enough to qualify as strength training. However, in many activities such as gardening, typically there are a handful of muscles that are used for the majority of the activities, leaving many other muscles untrained. This can cause muscular imbalances that lead to tendonitis. It may also impair flexibility and mobility over time.
The same point can be made of those in labor intensive jobs. I've heard many times, how they "don't need to exercise" because they get so much at work. Again, however upon further examination what you almost always find, is a handful of muscles that get used repeatedly and a bunch that do not get used at all.
The moral of the story is, a workout or fitness program does not need to necessarily train all muscle groups. It is important to take into consideration what you do for work and recreation, then tailor the workouts to address the muscles that need the exercise most, while also prioritizing the flexibility training to the muscles that get exercise the most. Taking such an approach will help reduce the risk of lower back pain, tendonitis, bursitis, and hernias.
An easy way to determine which muscles are likely getting all the exercise and the ones that are not receiving much is to look at the most commonly repeated tasks. If you find you perform a lot of bending over at the waist, you likely are training the lower back frequently. In this case you want to prioritize stretching the back and training the muscles on the opposite side of the body (abdominals). Let's say you find a majority of the tasks require pulling movements. In this case you want to prioritize stretching the lats, biceps and upper back, while training the pushing muscles (chest, triceps, anterior deltoid).
Remember a balanced body is a healthy body. If the body is not healthy, there is an imbalance somewhere.