Friday's sprint went without incident, so I figured I'd try the other end of the spectrum: constant heart rate. I haven't been able to accomplish that while running, so I figured I'd try it on a bicycle.

Unfortunately, I picked my daughter's 34-inch bicycle, instead of my wife's 36-inch. Even with the seat adjusted all the way to the top, my legs were never fully extended. My thighs are sore.

My seat is sore, too, of course. I hope that both problems resolve themselves after a few more rides.

I needed the gears to keep my heart rate down on the small inclines, and to keep it up on the small declines. But I stayed pretty close to 130 the whole time: I only needed four or five reminder beeps.

I went 4.95 miles; it's only 6.25 miles to work. Maybe I can get my wife to drop me off with a bike, so I can start riding home one day a week!

My run went well enough. I didn't have any trouble with my knee, anyway.

Saturday it actually swelled up a little bit. Still no pain, just stiffness. Ibuprofen doesn't help, ice pack doesn't help... the only thing that helps at all is sleep. When I wake up in the morning, I don't have any problem at all.

I'd go to a doctor, but I've got a big event at work. I'm stuck from 8 to 5.

I'm not running again until this is resolved. I'll probably get a chance on Thursday.

For my run on Wednesday, I decided to walk as quickly as possible during my resting intervals. It didn't keep my heart rate in an aerobic zone, but I thought it might cut my time. Not much: 42:06 isn't remarkable compared to my recent times.

Wednesday evening we ate at Texas de Brazil, an all-you-can-eat Brazilian steak house (churrascaria). Thursday morning I noticed that my right knee was stiff. Not swollen, not painful, just... stiff. It continued all through Thursday, and it didn't respond to ibuprofen the way that swelling does.

I don't know if this was caused by gorging on meat or some unnoticed injury I sustained. I've completely blown my diet, and I want to get back on the workout train, but I'm scared of running like this.

I went to bed early, and this morning I seem to be okay. Not perfect, but okay. Luckily my route has several "bail" points. I'll give it a try and see what happens.

My legs have were really sore yesterday. I suppose that's the expected result of a 9-week hiatus, though. I'm afraid to check my weight, especially with all the holiday binging I've been doing.

This morning, while I waited for Tatiana to get ready, I set the zone alarms on my new heart rate monitor. The American Heart Assocation guidelines were pretty vague: they said my max heart rate was 220 minus my age, and that I should exercise between 50% and 85% of my max. The guidelines that came with the heart monitor said my max was 219 minus my age, and offered three zones that I could exercise in.

I wound up setting my zones to 120 - 141 BPM. This was the aerobic zone, and it fell within everybody's guidelines. I should be pretty safe.

The plan is to run until I set off my high alarm, then walk briskly until I set off the low alarm. Rinse, lather, repeat. It's my hope that this "heart rate interval" exercising will be essentially identical to aerobic exercise, resulting in quick weight loss and cardiovascular health.

The run itself was both outstanding and disappointing. I wound up walking much more than I expected; it seemed like I couldn't go more than 100 meters without setting off my high alarm, no matter how slowly I tried to pace myself. The balls of my feet hurt pretty badly from rubbing inside the shoes. My overall time was a dismal 14:09 pace, a total of 45:36 for the whole run.

On the bright side, this was the easiest run ever. I was never really breathing hard. I had plenty left over for a sprint to the finish line. My knee didn't even hurt! I could've run a whole marathon on these intervals.

I'm actually looking forward to running again on Friday! I just need to get some padded inserts. Maybe I could wear two pairs of socks.

I've been improving, slowly, doing my heart rate intervals. I've never had a problem with energy, I've never been out of breath; my only complaint is that it's so slow: the morning 5K that used to take 30 minutes now takes 45.

At the end of every run, though, I've felt like I could do another. Which led me to wonder whether I could take on a marathon.

My friends who have run in marathons tell me that my 14:00/mile pace is acceptable, and that I could start training. The websites say I'd need to run a lot more (which I really don't have time to do).

I thought, "I'm doing something new here. Nobody has information about running a marathon on heart rate intervals. Why not try a run on the weekend just to see how far I can actually go?"

My family practically laughed at me.

I suppose I'll have to be my own support this time. I'm not saying I can keep running for four hours, or twenty-six miles. I just want to see how far I can go, and maybe make it a regular weekend running thing.

I'm not dead yet! Although, according to my wife, I probably should be.

I stopped running for 9 weeks so I could spend more time on some other projects. (My last run was 2010-11-17.) For Christmas, my wife and kids got me a heart rate monitor with zone alarms. Just what I wanted! Today, I finally went out running.

It was even harder than I expected. The muscles in my legs protested with every step. I ran until I felt uncomfortable: I was really hot, my breath was labored, and my heart was beating like crazy. How crazy? 175 BPM or so.

I didn't know how bad this was until my wife turned pale when I told her. I didn't find it much worse than my previous running; it didn't feel like I was in any danger. But apparently it's really close to my max heart rate.

At the time, I didn't realize, but I was too uncomfortable to continue. So I walked until I hit 120 BPM, then ran again until I hit 170. Near the end of the run, I adjusted it to 130 - 170.

The run took 39 minutes, and I was exhausted at the end. It took two laps of the sidewalk outside my house for my heart rate to go down to 120 BPM. My right knee was hurting a little bit.

I didn't get to tell my wife the whole story. She panicked as soon as she heard "175". I'll be setting my zone alarms within the American Heart Association guidelines for my next run.

It's hard to run a fitness blog when all you can post is "did it again today".

Today I'm skipping.

I haven't skipped in more than a month. I haven't even slacked off. I've got my 5.1K route, and I run it in a little under 35 minutes, even in 80+ degree heat.

Yesterday I mowed the lawn. Foot-high grass everywhere, two-foot high grass and weeds in many places, and I forgot that the mower had self-propulsion until I was 3/4 of the way through. My hands hurt.

I'm skipping today.