Sylvester Stallone’s movie Rocky was one of the most successful films in the 70s. The movie was directed by John G. Avildsen and the movie hit the big screen on 21 November 1976. Stallone rose to prominence in this film after being one of the most sought-after performers following his appearance in Rocky.  Many people remember the 76-year-old actor Rocky. 
Sylvester Stallone at an event
No doubt, there was so much blood and sweat shed during the making of the film. One of the most talked about scenes from the film is when Rocky aka Stallone runs through the streets of Philadelphia.

John G. Avildsen explained why he opted for the Guerrilla style for filming Rocky 

Sylvester Stallone at an event
Sylvester Stallone’s morning Rocky run shot is one of the most loved scenes from the 1976 movie Rocky. The director John G. Avildsen explained that he shot through guerilla filmmaking techniques as they had very limited resources. The late director said when Stallone was snaking through the streets of Philadelphia they were also trying to improvise the scene. Avildsen stated that when he saw the Italian Market full of food stalls he saw it as an opportunity to film the scene more naturally. The market scene was shot twice, the first time it was shot with a 35mm lens, and the second time it was shot with a 75 mm lens.

A stall owner can be seen chucking an orange toward Rocky in the Rocky Run scene, which was also shot quite naturally because the owner had no idea they were filming for a movie. As Stallone caught the orange thrown at him, the directors and editors were able to improvise the scene.

Sylvester Stallone’s every joint inflamed during the filming of the push-up scene for Rocky 

Sylvester Stallone in Rocky
Stallone was in great shape and he was also a gym freak who knew about the different exercises. He introduced the director to one-hand push-ups and Avildsen liked it and decided to film it for the movie. While talking about how Stallone filmed the hand push-up scene, Avildsen said,
“Great, just do it again, and let’s get it on film.’ The script had a shot written for several two-handed push-ups, but he said that something crazy happened every time the camera rolled and before I knew it, he was flying from one hand to another doing an exercise that no boxer in his right mind would ever do.”
He further added,
“He later said he inflamed every joint in his body but thought it was worth it for the sake of the picture.”
The Lean On Me director also stated that during the filming of the movie, the main focus was on his physical look because he was playing a boxer. He stated that they attempted to capture more shots of his muscles and physique because they were a crucial aspect of the film.

Source: DGA; IMDB