I've now been running for five weeks since my four-week layoff due to stress fractures. My focus has been on easing back into running, monitoring my symptoms and staying healthy. My weeks have been:
March 7: 10.5 miles
March 14: 9 miles
March 21: 11.8 miles
March 28: 18 miles
As for pace, I've been running what has felt like a natural, easy pace. But this natural, easy pace is slightly faster than what is was pre-injury. Before the stress fractures, my average training pace in January was 9:03-- and that includes over 10 miles of speedwork. In March, my average training pace was 8:53, and that includes only 3 miles of anything that could be considered "speed". Given that, my perceived "easy" pace seems to have dropped by about 15 seconds per mile. I attributed this to having fresh legs. You're obviously going to feel better when you are only running 10 miles a week as opposed to 50.
Even though I almost always wear a heart rate monitor, I decided not to wear one when coming back from injury. I also don't wear one in the few weeks following a marathon. The reason is that I don't want to get upset by how high my heart rate is for paces that used to be easy for me. I want to be in denial about my suspected loss of fitness! I thought that wearing a HR monitor would be highly discouraging so I avoided it for a month.
But on Friday evening, I decided to use it. I was really hoping that my heart rate wasn't going to be ridiculously high, causing me to be in a bad mood the rest of the evening and probably the entire weekend. But I was prepared for the worst. I was prepared for my "easy" pace to have a heart rate in zone 3 (marathon pace zone) and I would just have to deal.
My husband and I went out for an easy five miles. Much to my surprise, my heart rate was actually lower than it had been pre-injury. We ran 5 miles at an average pace of 8:45 and my average heart rate was in my "recovery" zone. As I was running, I kept looking down at my Garmin in disbelief. At first maybe I thought it wasn't getting a correct reading, but it was rising with the uphills and lowering with the downhills. And based on effort level, it did feel easy.
On January 7, I ran 5 miles at a pace of 9:22 and my average HR was 149. in Friday, I ran 5 miles at a pace of 8:45 and my average HR was 149. Whoa. The elevations for these runs were roughly equal. I'm skeptical. Very skeptical. Yes, I have been doing a good amount of cross training but if this data is to be believed then that's a significant increase in fitness!
Last weekend I decided I was ready for my first tempo run. I ran 2 miles at a 7:16 pace. 7:16 has never been my tempo pace, but it just felt tempo-ish. Of course, I didn't have my HR monitor to know for sure.
Today, I ran a 2.5-mile tempo, with the HR monitor. Once again, the average pace was 7:16. My avg. HR was right in the middle of my tempo zone. It got higher towards the end, but my max HR was still well within my tempo zone (zone 4). Don't get me wrong-- this was a very challenging workout. Especially because of the wind. It was a huge mental struggle as I wanted to stop after just one mile. But I kept reminding myself how important these workouts are.
So I'm thinking I should trust the HR data and be elated that I have actually gained fitness during my layoff. Of course, I haven't raced yet. But all signs point to a strong return!!!!