Fitness Robot: From Gym Spotters to ABB Cobots

How the fitness robot grew from human spotters, Zander machines and Nautilus cams to motorised smart spotters, and how ABB GoFa cobots fit in strength training.

INDUSTRIAL ROBOTICS

Chat With Robot

10/6/20265 min read

A fitness robot today rarely looks like a robot. It is usually a cable machine with electric motors in place of a weight stack, a camera or sensors that watch each rep, and software that lowers the load when you start to fail. This post traces strength training from personal instructors and human spotters to Gustav Zander's machines, pin-loaded weight stacks and Nautilus cams. It then looks at the motorised strength machines shown at IFA 2026 in Berlin, where ABB's GoFa cobot and welding robots fit, and what still stands between a home gym and a true robotic spotter.

A man in a yellow shirt stands behind a bench, hands near the barbell of a man lying on it
A man in a yellow shirt stands behind a bench, hands near the barbell of a man lying on it

A sailor spots a shipmate's bench press in a base gym, the job smart strength machines now try to take on. Photo: U.S. Navy / Lt. Nicole R. Schwegman via Wikimedia Commons (public domain)

How trainers, spotters and weight stacks shaped the gym

For most of history, strength training needed another person. The strongman Eugen Sandow turned physical culture into a business around 1900, touring with demonstrations and drilling groups such as the police in Bendigo, Australia. In a gym, the spotter played the same part for heavy lifts. A partner stands behind the bench, keeps hands near the bar and lifts it off the lifter's chest when a rep stalls. That is still how bench pressing is taught in military and school gyms, and it is the job that the newest machines try to automate.

Old photo of a row of men in shirtsleeves raising their arms in an exercise drill outside a brick building
Old photo of a row of men in shirtsleeves raising their arms in an exercise drill outside a brick building

Eugen Sandow instructing police officers in Bendigo, Australia, in the early 1900s. Photo: Wellcome Collection via Wikimedia Commons (CC BY 4.0)

The first serious exercise machines came from Sweden. In the 1860s the physician Gustav Zander began building apparatus for what he called medico-mechanical gymnastics, and he opened the Zander Therapeutical Institute in Stockholm. His machines used levers, sliding weights and cranks so a patient could train one movement at a set resistance without a therapist pushing back. Zander showed them at the 1876 Centennial Exhibition in Philadelphia, where they won a gold medal, and Zander institutes later opened in many cities in Europe and beyond.

A man in a suit sits in a wooden machine and pushes a padded lever arm with a weight on a long rod
A man in a suit sits in a wooden machine and pushes a padded lever arm with a weight on a long rod

One of Gustav Zander's medico-mechanical exercise machines, photographed around 1892. Photo: Tekniska museet / Wikimedia Commons (CC BY 2.0)

Gym machines as we know them arrived in the twentieth century. Jack LaLanne opened a health club in Oakland, California, in 1936 and designed early cable pulley and leg extension machines. Harold Zinkin's Universal Gym, founded in 1957, put eight or ten exercise stations on one frame, and users picked a load by moving a pin in the weight stack. Arthur Jones began selling his Nautilus pullover in 1970. Its cam replaced the round pulley, so the resistance changed through the movement to match how strong the muscle is at each angle.

Close view of a gym machine frame with a cable, pulley and a stack of numbered weight plates
Close view of a gym machine frame with a cable, pulley and a stack of numbered weight plates

A pin-loaded weight stack machine in a commercial gym. Photo: Alick18 / Wikimedia Commons (CC BY-SA 4.0)

Motors, sensors and smart spotters in gyms since 2018

The weight stack is now being replaced by motors. Tonal, founded by the engineer Aly Orady, launched in 2018 with electromagnetic resistance from 5 to 200 pounds and a Spotter mode that reduces the load when the user struggles. At IFA 2026 in Berlin, Speediance showed the Gym Monster 3 with up to 100 kg of resistance set in 500 g steps, the 3S with 120 kg, and the Gym Monster Ultra with two 1,000 W direct drive motors and 33 cable positions. Its Smart Spotter mode watches movement speed and lowers the load when a rep slows down.

A shirtless man pulls two cable handles together in front of his chest in a gym
A shirtless man pulls two cable handles together in front of his chest in a gym

A lifter doing cable crossover flies on a cable machine. Photo: Nenad Stojkovic / Wikimedia Commons (CC BY 2.0)

In a narrow sense these machines are robots, since a control loop reads sensors and decides how hard the motors pull. In its roundup of the best fitness tech at IFA, Gadgets & Wearables put Speediance's connected strength system alongside smart rings and trackers, because the same data (reps, velocity, training volume) now flows between the machine and a wristband. The Ultra adds Eccentric, Chain and Fixed Speed modes, each one a different rule for how the motors respond to the lifter. Speediance launched the Gym Monster 3 in the United States on 18 September.

A woman guides the white arm of an ABB GoFa cobot by hand over a desk with small speakers
A woman guides the white arm of an ABB GoFa cobot by hand over a desk with small speakers

Moving an ABB GoFa CRB 15000 cobot by hand to teach it a path. Photo: ABB

ABB does not make fitness equipment, but its GoFa CRB 15000 cobot handles the same problem a robotic spotter faces: working with force right next to a person. GoFa carries 5 kg, reaches 950 mm, has torque sensors in all six joints and stops when it feels unexpected contact. People can move it by hand to teach a path, which is how coaches demonstrate a movement. In factories that build gym machines, steel frames and weight stack guides are welded, which is standard work for ABB arc welding robots such as the IRB 1520ID. ABB has not announced a fitness customer, so both uses are possibilities.

An orange ABB welding robot arm next to a rotating positioner in a workshop
An orange ABB welding robot arm next to a rotating positioner in a workshop

An ABB arc welding robot with a positioner that turns heavy parts, the kind of cell used for steel frames. Photo: Ana 2016 / Wikimedia Commons (CC BY-SA 4.0)

What a true robotic spotter will need at home and in the factory

Cable machines can already spot you, because a motorised machine can reduce its own load. A loaded barbell has no motor, so free weights are the harder case. A robotic spotter would have to sense a stalled rep, take the bar's weight and return it to the hooks without pinching hands. The AI coaches shown at IFA already track movement in three dimensions, so much of the sensing exists. What does not yet exist in home products is an arm or rack that can safely catch 100 kg or more over a person's chest.

A man in a red shirt grips a loaded barbell over a lifter on a bench while others watch
A man in a red shirt grips a loaded barbell over a lifter on a bench while others watch

A strength athlete spots a heavy bench press at a Navy gym in 2010. Photo: U.S. Navy via Wikimedia Commons (public domain)

Safety is the hard part, and industrial robotics has rules for it. Collaborative robots like GoFa follow power and force limits so contact with a person stays below set thresholds, and SafeMove adds speed and zone monitoring on ABB controllers. A spotter has the opposite job. It has to push hard and fast, on purpose, close to someone's face and neck. That needs certified safety functions and redundant sensors, much as rehabilitation robots need medical approval, which we covered in our post on robotic rehabilitation therapy.

A white ABB cobot arm with a gripper stands on a wooden table with speakers and boxes
A white ABB cobot arm with a gripper stands on a wooden table with speakers and boxes

An ABB GoFa CRB 15000 cobot at a work table in an open office. Photo: ABB

Cost and skills will decide how far this spreads. Smart home gyms already sell at premium prices, and a robot that catches a falling bar would add actuators and safety hardware on top. Public gyms and outdoor fitness parks may adopt connected machines first, since one machine serves many users. Engineers who want to build one will need the skills factories already use, such as force control and safety zones, and they will usually test the motion in simulation first. You can practise the same ideas in RobotStudio before any real arm moves near a person.

A blue outdoor exercise machine with arms and a seat on a concrete pad in a park
A blue outdoor exercise machine with arms and a seat on a concrete pad in a park

An outdoor multi-gym station in Bluhm County Park, Michigan. Photo: Chris Light / Wikimedia Commons (CC BY-SA 4.0)

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