Re: Training over 50
Like you, I will be turn 54 this year as well. I first started Aikido in the mid 70s while overseas in the Navy, but drifted away after returning to the states since Aikido dojos in the US were very few at that time. However, I started up again a couple of years ago and now train two to three times a week and try to do at least two seminars a year. Mostly, I have found that flexibility has diminished as well as stamina. I normally train with a fast paced group in a college Aikido club affiliated with the ASU, and on occasion train at an independent dojo whose Aikido curriculum is actively supervised by Ellis Amdur and is physically challenging as well. At times I find it hard to keep up with the fast pace and feel bad when I have to sit out on occasion just to catch my breath. The problem is not with taking ukemi; falling is easy, but it is the constant picking yourself up off the mat that wears you down quickly. The physical limitations I have are a bad knee and troubled shoulder. With the shoulder, I just watch the ukemi on that side and tap out quickly on the arm bars and pins. However, the knee really limits suwari waza, and shikko is totally out. Sitting seiza is not a problem, but moving on the knees just does not work. Therefore, for suwari and handachi, I focus on staying centered and move uke around me; works well if done right.
As mentioned above, I would feel bad when I could not keep up and had to sit out because I felt I was not giving my partner as much as I was receiving. However, I came to understand that it is the quality of training and not necessarily the quantity that is important. If I could not perform the technique properly due to my exhaustion, it was not benefiting me nor my partner. I found that by sitting out one series, or limiting the technique practice to stopping before the fall, I could regroup and pickup at the next technique and perform as expected - this I feel is more beneficial to the training for all concerned.
I guess the important thing to remember is to be aware of your limitations, perform within them, and stay focused on your training objectives. Oh, the most important thing - have fun!