I'm a senior citizen as of this week with a titanium knee replacement. My first day I I could only do 1/4 the first workout. I will need to take an ibuprofen before I try it again tomorrow. I will keep replaying day one until I can complete it. These legs have not jogged in years. I will stick with it though, or maybe the Lord will bless me with a quick and fatal heart attack lol. Staying with it!