Causes of lack of strength

Other conditions
1

I have always suffered with varying degrees from a lack of motivation, concentration and basically what is defined as 'lazyness'

Until this March, I had one day in which I felt like superman - did a days work, mowed the lawn, mowed it again 5mm shorter, cooked dinner, spent 2.5 hours on focused CAD work, bought 3 things from ebay in 10 mins (would normally spend hours on each one) then put the kids in the bath, painted the kids bedroom then went to because I had to get up early but I wanted to do another coat of paint.

One measurable change was that I could quite easily do 10 presss ups that day and yet before and after I struggle to do 1.

I know of nothing which can cause an increase in strength like that so I figure it must be nerve or cell function related or horomone or something like that.

I am at a loss of what to look into next - there seem to be too many avenues to explore.

Any help finding specific terms to research or known ailments which sound similar would be great because it is very hard to Google something when you don't exactly know what you are looking for.

2

i would look into getting an emg/ nerve conduction test done and if they are normal then its probably nothing to worry about.

3

If you go through periods of almost hyperactivity and then go through a slump and feel listless,you could be Bi Polar.

 This can be mild,which would fit your description or of course there is an extreme,when sufferers go from an extreme manic high to a depressed low.  You may benefit from CBT.....cognitive behavioural therapy,which is talking to someone and getting to understand your highs and lows. It sometimes helps just to understand what is happening and then you can deal with it. Its not serious,but if you feel it is interfering with your life,do see a doctor.