The document discusses the efficiency of muscle work. It defines efficiency as the ratio of mechanical work output to total metabolic cost, which can be calculated from oxygen consumption. The efficiency of human muscle has been measured at 18-26% for rowing and cycling. The quadriceps muscle, a large thigh muscle, has an efficiency that has also been measured. Maintaining good muscle activity and using electrical muscle stimulators can help target the communication system between the brain and muscles. The quadriceps contributions to energy generation and dissipation at the knee joint were also examined during different phases of running. Maintaining mechanical efficiency is important for exercise and knee rehabilitation.

1. EFFICIENCY OF MUSCLE WORK
Kinesiology
FEBRUARY 27, 2017
SCHOOL OF PHYSIOTHERAPY
KING EDWARD MEDICAL UNIVERSITY, LAHORE

2. Efficiency
The efficiency is defined as the ratio of mechanical work output to the
total metabolic cost, as can be calculated from oxygen consumption.
Human Muscle:
The efficiency of human muscle has beenmeasured (in the context of
rowing and cycling) at 18% to 26%.
Quadriceps
Large muscle in front of the thigh, the action of which extends the
leg or bends the hip joint.
It is a two jointed Muscle(TJM): A type of muscle which is flexor at one joint
may also be a flexor or extensor at another joint.
Efficiency of Quadriceps:
The message system that works between the brain
and the muscle has to be targeted to enable good
muscle activity to occur.
Another way is to use a piece of equipmentcalled an
electrical muscle stimulator (EMS), which sends a
small electrical current into the muscle it is placed
over.

3. Quadriceps muscle contributions to energy generation and dissipationat
the knee joint during stance, swing and flight
phases of level running
Mechanical Efficiency
Exercise and is one of the most common
resistance training type of exercise used to
enhance performance in sports and in knee
rehabilitation as it produces greatestneural activation than the majority of
weight-bearing knee extension exercises.
Exercise at a constant work rate have estimated that ATP utilization per
work unit either decreased or increased over time during exercise.
The blood flow to the exercising muscle and the lactate released from
muscle to the blood stream is highly restricted,power output declines over
time and the external mechanical work produced during each muscle
contraction remains constant.
In hip flexion during standing and sustained stance-phase knee flexion
during walking, may be critical for balance control with trunk-flexed
postures