The results of the augmentations on the successful candidates were unprecedented; the SPARTAN-IIs performed well beyond the projected capabilities. Dr. Halsey suspected this to be due to inexplicable, synergistic effects resulting from all the augmentations acting in concert. Combined with the Spartans' intelligence, seamless teamwork and unyielding drive for success, the augmentations made them nearly unstoppable against any conventional combatant. Chief Petty Officer Franklin Mendez stated that after the augmentations the Spartans would only get better as they adjusted to the changes. Therefore many of the Spartans' attributes have increased through time and acclimation.
Only a few months after augmentation procedures, the SPARTAN-IIs were capable of running at speeds exceeding 55 km/h or 34.2 mph. Kelly-087 was noted as capable of running even faster. Later during the Human-Covenant war, while in her Mark V MJOLNIR armor, Kelly-087's top speed was 62 km/h or 38.5 mph. John-117 has been noted to have run at around 105 km/h or 65.2 mph during a MJOLNIR Mark V training exercise; however, his Achilles tendon was torn because the strain put on his body was unsustainable.
The SPARTAN-IIs were capable of lifting at least three times their body weight without the aid of their MJOLNIR Powered Assault Armor, when they were 14 years old. During their initial exercises in Reach's titanium mines, after recovering from the augmentations, the Spartans completely overpowered trainers wearing Mark I exoskeletons, outrunning their automated targeting systems and dismantling the heavy combat suits with their bare hands. A kick by John-117 flung one of the exoskeleton-clad men eight meters.
Despite the carbide ceramic ossification rendering the Spartan-IIs' bones "virtually unbreakable", they can still be broken by extreme physical trauma. Examples of this include Kurt-051's ribs being broken by a Hunter's shield strike, Otto-031 breaking his ankle upon falling from a great height, and Douglas-042's left shoulder being broken by Atriox.
Their reaction time, while impossible to chart accurately, was estimated to be twenty milliseconds. The Spartans' reaction times were noted to be significantly faster in combat situations or with assistance from an AI. The reaction times of the SPARTAN-IIs were so fast that they, in heightened states of stress, were able to think, react and see things as if everything around them were simultaneously occurring at both a slow and rapid pace - a phenomenon dubbed "SPARTAN Time" by Kelly-087. The motion of a Spartan in combat is nearly impossible for an outsider to follow, their movement appearing as a blur. These reflexes allowed Spartans to successfully dodge gunfire on certain occasions. SPARTAN-IIs are also known for their sharp eyesight, their occipital capillary reversal allowing them to virtually see in the dark.
When wearing MJOLNIR armor, a Spartan's strength is boosted significantly. During the Battle of the Rubble in 2535, Adriana-111, while clad in Mark IV armor, used her enhanced strength to lift a Mongoose by the handle bars and ram several Grunts with it. She followed up her maneuver by using the Mongoose as an improvised hammer, smashing three Grunts into the ground, pulverizing them in the process. During the Battle of the Etran Harborage, the three members of Red Team (Jerome-092, Alice-130, and Douglas-042) defeated a force of over twenty Stealth Sangheili in close-quarters combat without sustaining any injuries themselves. A MJOLNIR-clad Cal-141 was capable of blocking a Jiralhanae Chieftain's gravity hammer swing with a single hand, dodging multiple swings from the Brute, using her enhanced strength to jump to great heights, and wounding the Chieftain with a few punches and kicks. As he was trying to delete Gamma Station's navigation data during the Fall of Reach, a MJOLNIR clad John-117 physically stalemated a Sangheili in a zero-g grapple and wrestled it for control over a plasma pistol; he successfully killed it by striking it in the face with his elbow and shooting it with the plasma pistol. During the Battle of Installation 04, a 41 year old MJOLNIR armored John-117 flipped a Warthog and later broke the skull of a Sangheili soldier with his fist, after it was weakened by a grenade.
During Operation: FIRST STRIKE, John-117 fought a Jiralhanae in close-quarters combat and successfully killed it through the use of Brazilian Jiu-Jitsu and a grenade, despite being physically over-powered by it. Additionally, Linda-058 shot the pilots out of two Banshee fliers as she was hanging from a titanium cable that was attached to her arm and leg.
While trying to secure the space elevator in Havana during the Battle for Earth, Fred-104 clad in MJOLNIR Mark VI, fought and killed a Jiralhanae warrior in close quarters combat with a well placed strike to the Jiralhanae's neck and the entire clip from his rifle. During the Battle Of Onyx, Will-043 engaged a Hunter pair in hand to hand combat, and succeeded in killing one by ripping the worms out of its body, after Linda-058 bruised its mid-section with her sniper rifle. In the same battle, Kelly-087 engaged three Sangheili in hand-to-hand combat, snapping the wrist of one Elite, taking his energy sword, and cutting two more in half with a single swing.
In 2553, during the boarding of the
Piety, Naomi-010, while clad in Mark VII armor, defeated a Jiralhanae with a single uppercut, breaking its spine in the process. During Operation: JOVIAN WHISTLE, Fred-104 successfully struck an Aggressor Sentinel to the ground and physically stalemated the drone as it started to push him around.
In 2559, during Second Ark Conflict, Jerome-092 single-handedly defeated numerous Jiralhanae and Sangheili inside the Enduring Conviction. He was able to hold a Jiralhanae Warlord's jaw and pull the Warlord to the ground despite its weight, while uppercutting another Jiralhanae with his shotgun.
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