I am looking for a way to see if one of my workouts is effective. I work on five to six day cycle where one of the days is usually done on a heavy bag with 6 rounds 2 minutes each with thirty seconds in between. I have some boxing training and experience. Is there a way to gauge the effectiveness of this workout or any other workout where an increase in weight or reps isn't entirely applicable?
Testing the efficacy of conditioning workouts usually rests on measuring the output of the workout, i.e. X per time unit, where X can be watts, miles, punches thrown, whatever. More vague methods of tracking progress include feeling fresh at the end of a workout, or being able to complete a given workout more quickly, being able to shorten rest periods, or being able to complete more rounds. Of course these all depend on maintaining a constant work output.
Resting heart rate is another possibility for longer-term tracking of conditioning capability. With your specific example of bag work, there's also the traditional method of testing boxing conditioning: spar a few rounds, or take a fight.
There are more complex tests as well, which involve measuring heart rate or other indicators, or even looking at daily blood work.