Cycling cardio and arms

Today I did my cardio on the cycle machine. Its difficult to see in the pic but I was on there for approx 20 minutes before I moved back to the treadmill. It was way more difficult to cycle probably because I am not used to it. I had the setting on 10 which was pretty difficult. Worked up a sweat within 5 minutes of being on it. After cycling I did approx 20 minutes of treadmill walking / jogging and moved on to arms

After cardio I moved on to arm workout which consisted of the following:

Bicep curls ( 35lbs each arm ) 10 reps x 3 sets

Tricep pulldowns (using own body weight) 10 reps x 3sets

seated bicep curls ( 25lbs) 10 reps x3 sets

Standing tricep pulldowns (10lbs) 10 reps x 3sets

Finished off with some stretching to cool down. I am noticing muscle gains at this point. My clothes are fitting differently (in a good way) and I am able to lift more weights.