Jio-Ken is a martial art style that allows practitioners to utilize strong and speedy attacks such as fists and kicks in their old age. The user's physical body becomes so strong, they aren't affected by physical pain. The user can also utilize qigong to store up their energy from youth for future usage.
Although seemingly for a comedic effect, Lao G can pull his soul back when he was apparently dead from senescence, coming back to life.
Yotsu no Kamae (腰痛の構え,Yōtsū no Kamae?, literally meaning "Lower Back Pain Stance"): Lao G takes a stance by bending his knees, leaning forward, and stretching his arms in front of himself while having both of his hand make the shape of the letter G.
Me no Tsukare (目の突枯,Me no Tsukare?, literally meaning "Eye Stab Wither"): While in the Lower Back Pain Stance, Lao G jumps forward and strikes his opponents eyes. Me no Tsukare (目の疲れ) means "eyestrain". This technique was first used against Chinjao.
Kata Kori (型氷（かたコリ）,Kata Kori?, literally meaning "Form Ice"): While in the Lower Back Pain Stance, Lao G jumps forward and strikes his opponents shoulder. Katakori (肩こり) means "stiff shoulders". This technique was first used against Chinjao.
Fushi Bushi no Itami (不死武士の痛巳,Fushi Bushi no Itami?, literally meaning "Pain Snake of Undying Warrior"): While in Yotsu no Kamae, Lao G jumps forward and strikes all of his opponent's joints before landing behind his opponent. Fushibushi no Itami (節々の痛み) means "joint pain". This techniques was first used against Chinjao.
Jioken Kyukyoku no Higi: Sento Ho-Ken (地翁拳究極の秘技戦闘保拳,Jioken Kyūkyoku no Higi: Sentō Ho-Ken?, literally meaning "Earth Old Man Fist Ultimate Secrete Technique: Battle Preservation Fist"): This technique allows Lao G to conserve his muscle powers from his youth, storing it for future use against any bodily degradation that may otherwise hinder his combat abilities such as injuries, sicknesses, and old age. After activating stored muscle power, Lao G's body enlarges, gaining drastically increased musculature, and releases steam-like smoke from his body. His strength and speed increase dramatically, effectively returning his strength to his prime. He can use new techniques in this form. This technique is very similar with Life Return and Gear Second. Hoken (保険) means insurance.
G no Kokuin (Gの刻印,Jī no Kokuin?, literally meaning "Seal of G"): After activating his stored muscle powers, Lao G dashes his enemy with high velocity and punches them with his G-shaped fist. Lao G leaves a G-mark on his enemy. It was first used to defeat Chinjao.
"Battle Preservation Fist" is similar in the abilities of Muten Roshi from Dragon Ball, who is able to restore his body to its former muscular appearance.
"Battle Preservation Fist" is also similar to Genkai's Reihado-ken from Yu Yu Hakusho. Through this technique, she can restore her body to the point where she was at her strongest.
↑One Piece Manga — Vol. 77Chapter 768 (p. 9),
Viola reveals that Lao G is a practitioner of Jio-Ken.