How long to ride and at what level?

I've finally gotten back into regular exercise and would say I'm in moderate physical condition. I've noticed over the past month of riding I'm feeling more and more fit every day.

I typically ride MWF about 10miles at about 13-14mph average speed. Then on Saturday's I ride eithe with a club or alone for a 20mi ride.

I'd like to improve both my speed and my distance, but having 3 kids under 4 I don't have an endless amount of time alone that I can ride.

What is the best way to get more fit and ride faster? Should I stick with shorter 10mi rides and push myself to go much faster? Or should I stick with my current speed and go farther? Or is there a middle ground somewhere?

I guess what I'm really needing info on is the best training schedule to increase my speed and fitness.

Intervals or hill repeats is what I've been told.

I get where you're coming from. Cycling is very time consuming.

I do two types of intervals. The interval is 8-10 minutes followed by 5 min recovery. The first one is heavy resistance with a slow cadence (under 60 rpm). This is called "muscle tension" and it really builds up strength in your legs. The other is a tempo interval -- find the resistance/cadence that takes your heart rate to a place just a touch below your threshold and maintain it for 10 mins. On the tempo interval, gradually work up to 20 mins. This is building up your cardio training and learning to how to ride longer without burning up your legs.

There's other lactic threshold intervals, etc. that are also helpful. You will find that year over year you will get better and better. I am 58 years old and ride 5 mph faster today than I did 2 years ago. So, I would imagine a younger person could gain fitness and improvement fairly quickly.

I agree that intervals are the way to go ALWAYS, but especially when training with limited time. I do the same types of intervals as the above poster, but save the low cadence variety for pre-season, or very early in the season, when I am in strength training mode. Once my on-the bike training volume increases, I cut back on strength training and work on different energy systems. Namely, my lactic threshold (LT) and VO2 max.

My LT intervals are 2x20min at my LT power (or heart rate, or perceived effort). Basically, these should be the hardest effort you can sustain for the duration without petering out before the 20min is up, but not having much left to go longer.

My VO2 max intervals are 10min interval sets with 5min of recovery in between sets. The 10mins are broken up into periods (2-min) of very hard effort (higher than LT) followed by "tempo" pace or an effort slightly below LT for 3min. and repeat. Usually do 3-6 sets of these. 6 sets hurt, so you'll want to build up to this!

Finally, to work on top-end power/speed, you can do short intervals 30sec-1min where you go all-out and then recover and repeat as many times as you can (8-15X)