Read the latest chapter in running columnist Mark Armstrong's pursuit of a sub 20-minute 5K

I may have bitten off more than I can chew with this sub 20-minute 5K challenge I've set myself this summer.

I'm enjoying the different training plan with its short bursts of intensity with all too short periods of recovery.

But it's as hard as training for a marathon, in a totally different way.

I've got absolutely no doubt that if I could dedicate all my time to running then I could go under 20 minutes…but I'm not an elite athlete as these columns all too clearly demonstrate!

Like most recreational runners I have to fit running around my life – it's just a hobby and my improvement as a runner can't come before my responsibilities to my family and job.

MORE: When is it time to abandon a training run?However, I must admit sometimes I try to get my daughter, Lara, to bed a little earlier and encourage her to choose one of her shorter story books just so I can get my evening run in a bit earlier…it doesn't always work though.

I'm definitely finding that the more intensive training is picking up a few more biomechanical weaknesses I didn't know I had. I went through a similar, niggly spell training for my marathons but, once my body adjusted to the long mileage, the aches and pains started to clear up.

I know the same will happen again in this training block but I need to be patient. I'm at the stage where a niggle could become an injury and I definitely won't get faster if I'm sidelined.

I'm treading carefully with my training and adjustments are being made all the time. I'm lucky enough to have Neil Featherby devising my program and the schedule he sets at the start of the week is never written in stone.

He emphasises the importance of keeping him informed of how I'm feeling so he can make tweaks to the schedule.

The plantar fasciitis situation has definitely improved since I bought new trainers…(okay two new pairs of trainers) but my hamstring is grumbling so one of the intensive sessions was changed to an easier run.

But I've still managed to get some good running in. After one particular session I re-laid my splits to Neil who messaged me with something that I thought about for days after.

'You're learning to be comfortable with uncomfortable'…and in those words he summed up what getting the best out of yourself is when it comes to running.

MORE: 'They thought my heart had stopped' - Chris Merrylees on the fright of his life at Brighton MarathonWhen I learn what my bearable pace is then that's when the faster times will come.

I'm back at my dad's this weekend, which means I've got the childcare to have a stab at the parkrun there in Bishop's Stortford.

I'm not putting any undue pressure on myself (any more than normal anyway) but it will be useful to see where I am. I haven't put together three quick miles in succession in my training yet and it will be interesting to see what I can cope with. My 5K personal best is 21:10 (set during a 10K) so it would be nice to go under that – we'll see.

Whatever happens there will be coffee and food after – I did say that I'm not an elite athlete.

I've got to give my wife, Alison, a shout out this week as she went on her first run this week since having our son, Logan. Fortunately she's a lot more patient than I am when it comes to running although having said that she is already talking about beating my marathon and half marathon times. Apparently she wants a couple of the household records back…