I have a query about thumb placement and thumb pressure. I'm on Stage 2 of the Beginners Course and am happily practicing all of my A, Am, D, Dm, E and Em chords. However it's the A chord where I notice this issue more-so.
Please note that I am also following this chord sequence from Justins Beginners Coursebook: A, D, Dm, A with 4 down strums per bar and @ 40 bpm (I was at 60bpm but I found some of the changes to be too difficult at speed and slowed it down).
The part where I have to strum 8 consecutive beats on A is where I'm having my issue. Because my index finger is so far away from the 2nd fret (as it naturally falls back towards the first fret given how Justin wants us to achieve an A chord at this early stage), I find that I have to press down quite hard on the strings to prevent the string from buzzing - and I've had many frustrating attempts at A where that one string will buzz horribly.
What I notice is that, because I have to apply extra pressure for that string, my thumb gets very tired by the end of strumming the two A chords (I have to hold that A chord in place for 8 seconds at 60bpm or 12 seconds at 40bpm). It's getting better as I practice daily but it's still a noticeable issue and has led to the following chords being that bit sloppier at times.
Is this natural early on to find the A chord so much harder to press down on? Is the thumb tiredness down to just a simple lack of finger strength - which will come with practice? Or am I placing something incorrectly?