Stride length while going uphill: Short or Long?

[ASTraveler]

What is the best stride length for conserving energy while going uphill on a trail?

When I am going up a trail with an incline of 10%-20% I find myself taking fairly short length strides, roughly 1/2 the length of my normal fast paced level ground walking. My pace with these shorter steps is about 2 strides in 1.5 seconds.   (Note that  the 1.5 seconds is an approximation.)

 I have at times, times switched to a longer stride, roughly the length of my normal level ground walking and slowing my pace down to the length of time I would be taking for the two shorter steps.  

Again, this is when walking on a steeper, usually rough terrain trail, or cross country. 

Any thoughts on which uses the least amount of energy?  

[balzaccom]

I tend to follow the strategy and tactics of cyclists.  Keep your pace steady, and adjust your stride to keep yourself moving at an acceptable speed.  If you're getting too winded, take shorter strides but keep the same rhythm going.

And I tend to count strides against my breathing.  Normal walking is four steps per breath (inhale for two and then exhale for two).  Steeper trails lead me to inhaling for two steps, exhaling on a third step.  And onreally steep trails I either inhale or exhale with every step.

I'm also a musician so this rhythm stuff makes sense to me.  My average on a bike is about 90 pedal strokes per minute.

I have yet to climb in the Himalayas, where climbers take two breaths for each step.

[ASTraveler]

Thanks.  I haven't paid much attention to my breathing and the number of steps I take.  I'll give it a try.

[Aaron Zagrodnick]

I find it more natural on steeper inclines to take shorter length steps at a quicker pace if I’m trying to maintain the same speed. On occasion though I will power through an uphill with longer strides, but my overall hiking speed would be faster. On overall speed I find that the downhills are interesting as well, for instance I usually hike at the same speed downhill as uphill. One person I hike with is slower uphill but faster downhill, so I’m usually waiting on the uphills and often catching up up going down the other side.

[ASTraveler]

I do find it more natural to take shorter steps at a quicker pace on steeper inclines. 

My main interest is energy conservation.  Wondering which uses less energy, short faster steps or longer slower steps on 15% to 25% inclines.  Or maybe it is a toss up.  The amount of energy expenditure being about the same?

BTW, I am a 75 year old day hiker who on occasion hikes 7-9 miles round trip with elevation gain/loss of 2,000-3,000 feet.  At home I walk 3-4 times a week at a park to stay reasonably fit.  The trail route I take covers 4 short 150 yard inclines which average about 10% to 15% with short sections of 20%-25%. The inclines are unmaintained rough and rocky trails.  The area between the climbs/descends is mostly level and varies from 100-300 yards.  Total distance is about 4 miles, a total elevation gain/loss of 700 feet on mostly rough rocky trails.