[運動したい](https://eikaiwa.dmm.com/uknow/questions/58325/)のに、何らかの理由でできていないなら、「not able to」でそれをはっきりさせることが大事だと思います。
「① I haven't been able to work out recently.」＝（[最近](https://eikaiwa.dmm.com/uknow/questions/36239/)運動ができていないんです）
もちろん、この後は「何故？」と質問が来るでしょうが、それはbusyとかinjured（怪我）で返せます。
大事なのは、運動の意欲はあるが、理由があってできていないこと、それを伝えるには「① I haven't been able to work out recently.」が良いと思います。
ジュリアン
Yukaさんが書いたように、「[運動](https://eikaiwa.dmm.com/uknow/questions/58325/)」のことよく"work out"を使いますが、"exercise"でもいいと思います。
I haven't had time to exercise lately
「最近運動する[時間がない](https://eikaiwa.dmm.com/uknow/questions/50193/)」という感じです。
lately は「最近」という意味になります。
"Do you do much exercise Mike?"
"Well, I used to do a lot
- triathlons, rugby, swimming, gymnastics. But lately I've become quite lethargic and...well...lazy, I suppose."
"Me too. I've haven't done much exercise recently either."
"I think I've been a bit of a couch potato recently
- just watching TV and eating snacks every evening.
I think we should both start doing something or we'll become really unhealthy!"
If you use a phrase like "I haven't been able to work out at all lately," the nuance is that you want to, but haven't been able to.
If you don't want to be as subtle, you can just come out and say:
- Recently I haven't had time to work out.
- I've been so busy that I haven't had a chance to make it to the gym.
- I'd love to work out, but I haven't had a spare minute lately.
"I haven't been able to work out at all lately," は仕事に行きたいけど何らかの事情で行けてないという意味です。
もう少し具体的に言いたい場合はこれらのフレーズを使えます：
- Recently I haven't had time to work out.
- I've been so busy that I haven't had a chance to make it to the gym.
- I'd love to work out, but I haven't had a spare minute lately.
No time for anything but a sedentary lifestyle...spending too much time seated and inactive
Not findng time to work out... or keep fit usually means we are "Desk Bound".
And living a "sendentary Lifestyle"...where we hardly move around much at all...
Computer terminals are often the cause of our sitting down "for hours on end".
But if we want to live longer and healthier we had better get up and do some exercises ...now and then:-D
運動する時間がないことや健康を保てないことを、"Desk Bound"（机にへばりつく）と言います。
"sendentary Lifestyle"（座りがちな生活）をするということは、ほとんど動き回らないという意味です。
コンピュータが"for hours on end"（何時間もぶっ続けで）座っている原因になっていることが多いですが、長く健康的に生きたいなら時々立ち上がって運動をしたほうがよいですね:-D
The sentences above mean that you have been too busy to get a chance to exercise the past few days. To get a chance means make something happen.
For example:
I never got the chance to watch that movie.
上記の文章は忙しくて、過去数日間運動する機会がなかったことを意味します。
「To get a chance」とは、何かを起こさせることを意味します。
例えば、以下のようになります。
I never got the chance to watch that movie.
映画を一度も見たことがありません。
As of late, I haven't been able to exercise because of time.
1. I haven't had time to exercise lately.
私は最近運動する時間がなかった。
lately
recently; not long ago.
"she hasn't been looking too well lately"
2. As of late, I haven't been able to exercise because of time.
後で、私は時間のために運動することができませんでした。
The expression "as of late"means :-
lately, recently, in recent times.
1. I haven't had time to exercise lately.
私は最近運動する時間がなかった。
lately＝最近。そんなに前ではない
"she hasn't been looking too well lately"
（最近彼女は元気がなさそうに見える。）
2. As of late, I haven't been able to exercise because of time.
最近、私は時間がなかったので運動することができませんでした。
"as of late"という表現は、最近、このごろ、近頃、という意味です。
Example Q: Have you been working out lately?
Example A: No, I've been preoccupied by work.
Example Q: How fit are you?
Example A: Not very. I have not been able to work out lately.
【例】
Q: Have you been working out lately?（最近トレーニングしてる？）
A: No, I've been preoccupied by work.（してない、仕事のことで頭がいっぱいだから）
Q: How fit are you?（体は元気？）
A: Not very. I have not been able to work out lately.（あんまり。最近トレーニングしてないから）
You can use any of the following phrases to explain that you haven't worked out for a time:
I've not trained recently.
I haven't worked out recently.
I haven't exercised recently.
I haven't been to the gym in a while.
しばらく運動していないと伝える言い方です：
I've not trained recently.（最近トレーニングしていません）
I haven't worked out recently.（最近トレーニングしていません）
I haven't exercised recently.（最近運動していません）
I haven't been to the gym in a while.（最近ジムに行っていません）
If you have not had the chance to exercise in the past few days or weeks, the sentences above can be used.
Some people prefer to exercise a few times a week if not daily.
If you were not able to do so recently it could be because of illness, a heavy work schedule or just a lack of motivation.
"I haven't been in the mood for the gym lately."
"It's been a while since I exercised."
ここ数日あるいは数週間運動ができていないなら、上記の文が使えます。
毎日でないにせよ「月に数回は運動をしたい」という人もいます。
「最近運動をしていない」なら、これは「体調を崩している」とか「仕事が忙しい」とか、あるいは単に「やる気が起きない」ということかもしれません。
"I haven't been in the mood for the gym lately."（最近ジムに行っていません）
"It's been a while since I exercised."（しばらく運動していません）
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