The short answer is yes, you can but we wouldn't recommend it. The better answer is, in a perfect world you would train on a 3 day on, 1 day off schedule (ex. train Monday-Wednesday, rest Thursday and so on). This is because we want you to be able to perform at maximal intensity during each workout. Without allotting time for rest and recovery, your performances may begin to suffer and it could lead to overtraining.
If you pursue another physical activity such as a sport, you will need to balance your work/rest cycles and be sure to allow for recovery. Sometimes, you will need extra days off or to consider a WOD as "active rest" done at a lower intensity.
On the other end of the spectrum, we do want to see people coming in on a regular basis. Again, the 3 on 1 off regimen is our recommendation. Of course, life doesn't always see it that way, there are jobs and family and other responsibilities that sometimes prevent you from getting in on that schedule. At a minimum, though, we want you in 3 to 4 days per week. Your success matters to us, and the only way to achieve that is if you come in.
For further information about ISP CrossFit, email Health Management Specialist Troy Torrence at firstname.lastname@example.org.