BIOMECHANICS OF HIP-HOP DANCE  By Edwin Robles Jr.

WHY SHOULD WE CARE? - Dancing since 8 years old. - Hip-Hop team since Sophomore Year of High School. - Professional Adult Dance Team – 4 Years – COOKIES!!! :] - Instructor/Director – Oceanside Dance Academy. - To understand the relationship between physics and dance.

WHAT IS IT? “HIP-HOP DANCE” - An artistic form/genre of dance where conversational and expressive movement is executed, usually accompanied with Hip-Hop music. - Beat heavy, rhythm, and speed. - Loosely also classified as “Urban” Dance or “Street” Dance. - Styles: Popping, Locking, Breakdancing/B-boying, New School.

WHAT IS IT? “BIOMECHANICS” - The study of movement for living organisms applying the laws and principles of physics. - Scientists study movement in cells, animals, humans, etc. - Aristotle, De Motu Animalium.

COMBINING BOTH IDEAS… - How the laws of physics and mechanics apply to Hip-Hop Dance. Ex. Force and Balance, Torque, Acceleration, Momentum, etc. - Experimental Analysis

CENTER OF GRAVITY + BALANCE - The downward force of gravity as it acts on the body as a whole. - Standing position. - Greater in hips in women and chest/shoulder in men. - Your C.o.G. cannot be moved from rest unless some net force acts on the body as whole. (Newton’s 1 st Law and 2 nd law). - In a perfect world, we could be considered motionless. However, this is not true.

MOTION WITHOUT TURNS  For every force exerted by the body against another object, the body experiences an equal and opposite force acting back on it.  Newton’s 3 rd Law.  To accelerate, shift center of gravity between the feet and the floor.  Starting in a lunge position or lower to the ground vs. standing straight up.

TORQUE  Force that causes a rotation.  Ballet: 4 th position allows dancers to turn more efficiently and increase the amount of turns they do.  T = F x d = I x α (rotational acceleration) (Newton’s 2 nd Law).

ROTATIONAL MOMENTUM  Recall elementary equation: p = m x v for regular momentum.  Therefore, the result of rotational motion.  Depends on 2 principles.  Size of torque exerted on the body.  Length of time torque is applied.

A CLOSER LOOK…  L = I x ω …. Looks like p = m x v! (unit analysis: kg x m/s).  Where, I is the rotational inertia (m x r^2) and ω (radians/s) is the turn rate (rotational velocity). L is greatest when legs and arms extended to the side compared to when they are close to the body. L and ω are inversely proportional. Change in distance of arms from rotation axis will change the rate of turn. Adults vs. kids in turns…