Threshold running

Do threshold running once a week. Training for a 9min/mile marathon in april so been doing threshold running at 8.3min/mile. Buillt the set up to 8mins * 4 with 90 secs recovery between. 

What would be most beneficial next, increasing the pace, increasing the duration, increasing the reps or decreasing the recovery? Or play with all of the above.

I dont do any fast interval training (I do hills however) so my intitial thought was to increase speed but any advice appreciated. Thanks. 

I'm following the Pfitzinger & Douglas schedule for my spring marathon, and one of the notable differences is the lack of interval training, and a greater focus on tempo-style sessions (e.g 5 miles at 10k to 15k race pace) to boost the Lactate Threshold.

Based on this, I'd say you want to extend the distance rather than the speed when training for a marathon.  You seem to be be half-way there as it looks like your currently doing just under a mile at high pace (with very little recovery between).  Ids 8.3 m/mile roughly HM or 10k pace?  

Are you following a training schedule for your marathon, as speed work should be part of an overall plan?

Based on your planned marathon pace of 9 min/mile, Mcmillan would predict a lactate threshold of 8:12 min/mile. Obviously this is based on planned pace so that may be your aim in raising the threshold.

For marathon training I prefer a longer threshold run similar to what stutry is doing. I do 4 to 7m a little quicker than my half marathon pace. I also did a treadmill session recently with recovery pace as my marathon pace, and then intervals at various paces around the threshold. That session generated a lot of sweat, but not sure how good is was in nudging up the threshold.

Hi - thanks. Its nearer my 10km pace. I'm not following a specific program, but doing one LSR, 1 or 2 middle distance runs, 1 threshold and 1 hills a week. I didnt put any speed work in as on a training day attended by full potential they suggested that thresholds and hills were more beneficial over speed work for a first marathon. I wouldn't have time to add another run in but maybe its worth alternating hills and speed intervals?

Personally I prefer to do threshold and hill repeats. The hill repeats are good for strengthening, running with good form, and on some of them I am hitting VO2 heart rates anyway - I see it as my '2 for 1' special 

Closer to race day I may drop one or two hill repeats in favour of intervals. A few plans include them, but they are often towards the end of marathon training such as the P&D plan stutyr mentioned. I am making it up as I go along this time so please take my words with caution

Increase your tempo run up to 6 miles (plus a mile or two iether end for warm up and cool downs) at 10k -1/2 marathon pace

thanks - why 6 out of interest? also by increasing reps or duration you think?

That's what I've read in the best books and what I've practiced for a couple of years. It works well. I think it would take too much out of you running further at that pace... and end up being a long run.

I do 1 or 2 miles warm up run followed by 2 miles at threshold and finish with 1 or 2 miles warm down run. I then increase the threshold section each week or so by another mile up to 6 miles.

Threshold pace is just slightly slower than your 10km pace, so you should find any more than 6 miles at that pace to be close to race pace and not something to try to acheive regularly in training.