I hurt lower back 3 times already, the worst one from deadlifts. I found the williams exercises for low back pain, on profile link, to be effective each time.

Here's the homemade dip station I use at home. See the link for more details.

Do lots of cardio, watch your diet and lift weights. Can't think much else for getting "toned" arms.

Forearm strength come in handy for grappling moves for the mixed martial artist. I think the best way to develop hand and forearm strength is through thick bar training. There are fat grips (adapters for a thick bar) in the market, but a bit overpriced for me. I use improvised thick bar grips that y...

Be aware though, that because close grip use more Tricep recruitment, you'd be advised to cut back on the weight, as your usual amount could be too hard. It might take you a set or two, maybe even a session or two to find a new weight, by adding a bit more each time, but it's safer that way than ju...

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Close grip bench presses workout your triceps with heavy weight. This exercise trains the chest too that's why you're able to add more weight. To focus on triceps, don't lower the bar too much (touch chest).

Which "under the arms" do you refer to? Lats? Triceps?

If it's tendinitis, then a PT may help. See a doctor to confirm. Therapy may last anywhere from 2 weeks to 4 weeks, but it will be well worth it. Tendinitis tend to recur if left untreated.