The fast four-legged runners or quadrupeds do seem to be advantaged versus bipeds in terms of the mechanics allowed by their anatomy. So to go even faster would require people to successfully adopt the running mechanics of four legged animals (running on hands and feet).
Coverage of the billion and soon to be multi-billion dollar transgenic medical, agriculture, industrial industry. [Mixing genes between animals to make cheaper drugs or for more productive agriculture]
DARPA is also spending 3 billion to enhance strength and endurance. So endurance enhancements combined with the muscle speed enhancements could allow sprinting for an entire mile run. This would mean 80 seconds to run one mile. 1 minute and 20 seconds. It could also mean about 40 minutes to run a marathon.
Chimpanzees have been estimated to possess five times human strength and gorillas supposedly have 10 times human strength.
Some gorilla's are believed to be able to lift 2 tons and can tear up trees.
Most human strength activities, such as weight lifting, involve a degree of skill as well as strength. It is possible that a human could bench press more weight than a gorilla, but that a could tear the arms off the human. Gorillas and humans have variable strengths. The gorilla has very strong arms, compared to a person. The speculation is that silverback gorilla are 5-20 times as strong as a human.
Maximizing human muscles with myostatin inhibition would be able to double the strength of most people.
There is also work on gene therapy to help tendon healing and there could also be gene therapy to strengthen tendons. Tendon healing improvement.
There is also the exercise pill that tricks the body into thinking it has exercised which improves muscles and tendons
The biggest societal gains would come if we can understand the brain and genetics enough to make safe and effective genetic and biological interventions to greatly boost cognitive performance. If an IQ point increase given to all people results in a 2% increase in GDP, then a 500 IQ point increase for everyone would provide an almost 20,000 times boost to GDP and a 1000 point increase would be almost 400 million times increase in GDP (if the one IQ point for 2% increase rule held all the way)
Nick Bostrom's Converging Cognitive Enhancement article refers to Herrnstein and Murray 1994 paper "The Bell Curve: Intelligence and Class Structure in American Life" Note: There is controversy surrounding the bell curve conclusions, because intelligence is controversial/political and social conclusions are controversial/political. Therefore, it is sometimes better to focus on whether economic or individual or group productivity is increased by some actions or not.
A lot of other major technology breakthroughs could occur over the next few years including breakthroughs in cognitive enhancement.
IQs have appeared to be rising at 3 points per decade through the 20th century. The causes were believed to be better health, nutrition and education.
Breakthroughs in education/training and cognitive enhancement could enable a magnification of the effect by ten times even without invasive procedures.
Craig Venter has discussed the possibility of increasing cognitive faculties by ten times using genetic engineering. Genetic engineering, stem cells, mind machine interfaces, virtual reality training and other high potential cognitive enhancement might enable such radical leaps in capability.
Vernor Vinge's ideas around intelligence amplification are discussed at the New York Times They are find more productive ways for humans to collaborate and for humans to be helped by computers.
Rapid progress with genome sequencing and dna synthesis and synthetic biology are setting the stage for radical genetic engineering advances
Genetic engineering at wikipedia.
Gene therapy progress and prospects on mitochondria disease from gene therapy journal
A view into the state of clinical gene therapy research.