Doing high reps at a light weight might be good as a metabolic conditioning workout (provided you are doing full body functional movements at high intensity) or it might be pretty much useless if you are doing things like curls and triceps kickbacks. Lifting heavy things is the only way to get stronger and getting stronger should be your goal regardless of whether you are a man or a woman young or old. Strength is the most important of the 10 components of fitness because it is the one that will improve your quality of life as you age. The stronger you are now...the stronger you will be when you are 80......being strong at 80 mean the difference between being able to get up a set of stairs or being able to pick up a bag of groceries. Cardiovascular conditioning is important...BUT NOT AT THE EXPENSE OF STRENGTH....WOD: 5 rounds of:
"Strong people are harder to kill"
9 Sumo DeadLift Highpulls (125 lbs/ 85 lbs)
6 Push Press (125 lbs/ 85 lbs)
6 Floor Wipers (125lbs/ 85lbs)
I lifted at 95 lbs. Finished in 11:xx.
Then later in the day I did a 5k run; time was 28:11.