Strong Resilient in Chinese / Japanese...

気の強い means strong-willed or strong of heart in Japanese.

Here's the character breakdown of this Japanese title:
気 (ki) spirit; mind; heart; nature; motivation; intention; feelings; essence.
の (no) possessive particle.
強い (tsuyoi) strong; powerful; mighty; potent; resistant; resilient; durable.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

不屈不撓 means “Indomitable” or “Unyielding.”

不屈不撓 is a long word by Chinese standards. At least, it is often translated as a single word into English. It's actually a proverb in Chinese.

If you want to break it down, you can see that the first and third characters are the same. Both mean “not” (they work as a suffix to make a negative or opposite meaning to whatever character follows).

The second character means “bendable.”

The last means “scratched” or “bothered.”

So this really means “Won't be bent, can't be bothered.” I have also seen it written as “Will not crouch, will not submit.” This comes from the fact that the second character can mean “to crouch” and the last can mean “to submit” (as in “to give in” such as “submitting to the rule of someone else”). This may explain better why these four characters mean “indomitable.”

Notes:
Some will translate this as “indomitable spirit”; however, technically, there is no character to suggest the idea of “spirit” in this word.
Other translations include indefatigability, indomitableness, or unremitting tenacity.

The first two characters can be stand-alone words in Chinese.
In Japanese, this is considered two words (with very similar meanings). It's more common to see the word order flipped to 不撓不屈 in Japanese.
The same characters are used in old Korean Hanja. Just like in Japanese, the words are swapped to 不撓不屈 creating a word pronounced “불요불굴” in Korean.

See 不撓不屈

See Also:  Tenacity | Fortitude | Strength | Undaunted

打たれ強い is often used as a martial arts term.

It means being able to take a lot of punishment or being able to take a hit. In Japanese baseball, it can also refer to the pitcher's ability to keep his cool when the batter gets a hit. 打たれ強い is generally about being resilient and strong in the face of criticism or adversity.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

強い体強い心 is a way to write “strong mind, strong body” in Japanese.

Each of the two lines starts with 強い (tsuyoi) which means: strong; powerful; mighty; potent; resistant; resilient; durable; tough; stiff; hard; inflexible.

The body is represented with 体 (the ancient version is 體, romanized as karada), which means: body; build; physique; posture; torso; trunk; health.

Mind is represented with 心 (kokoro), which can mean heart, mind, or soul, depending on context.

強い體強い心 is not a common phrase in Japanese, so it's not the most natural title for calligraphy. In English, you might want to write it, “strong mind, strong body” but, “strong mind, strong body,” is more natural in Japanese.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

This Chinese word means resilient or “tough and strong.”

強い means strong, potent, competent, domineering, tough, brawny, powerful, healthy, rugged, skilled, resilient, solid, or fierce.

This word is ambiguous without context, so it can mean any or all of these things if you wish.