I am just re-booting my running following a long absence due to an Achilles tendon injury. While I have the basic fitness, I need to know how far I can push the tendon, so have gradually built up (in the first month or so I could barely walk more than 1 km without hobbling). I started just seeing if I could run 1 min and walk the rest without inflaming the tendon). Then I did 3x 1 min with walk in between, then 5, and then took the plunge and did Week 1 run 1 8x1min. The next run I did Week 2 (skipped the others as my fitness wasn't the problem - just caution). Week 2 increases the time running by just 1 minute to 9 mins total (6 x 1'30). The next two I did a Week 3 run, which is exactly the same total of 9 (1'30 + 3 + 1'30 + 3). In fact I extended the final 3 to 5 - like I say it's a whistle-stop tour to make sure my tendonitis doesn't flare up.
Then today I did a Week 4 run. It struck me that this is the biggest incremental increase in the total time running in C25K - from 9 minutes up to 16 minutes, a whopping 78% increase from Week 3.
I seem to have survived! Yay! 🤞🤞🤞
But I remember on this forum people get very nervous over Week 5 Run 3 - 20 whole minutes running without a break.
But look at the total increase - from 16 to 20 minutes - just a 25% increase compared to the 78% increase for Week 4.
Now of course, you don't get a break - but believe me, you won't need one as you will have learnt what is your sustainable pace.
After that, the increases get less and less. Week 6 goes from 20 to 25 (20% longer), Week 7 doesn't change, Week 8 25-28 (12% increase) and Week 9 28-30 (7% increase).
So it's my contention that Week 4 is the toughest ramp up. So don't panic about Week 5 run 3!
(Mind you, I bricked it before that run the first time round! But I needn't have). If you managed the heft from Week 3 to Week 4 you're well on the way!