Various accessories can make working out on treadmills much beneficial and more interesting, but they can also distract a trainee and hamper proper workouts.
It is nice to have a heart rate monitor strapped around your chest, especially if you have heart related issues, but to have a bunch of wires connected to the body while walking and/or running can be counterproductive and can lead to injuries.
Technology is a fine thing as long as it serves us, not vice versa.
Dumbbells are type of free weights - short bar with weight plates on both ends. In combination with treadmills, dumbbells can be used for isolation or multi-joint exercises used for strengthening and toning the body.
Fixed size dumbbells are commonly found in every commercial gym as the dumbbells set positioned on easily accessible dumbbells' rack(s).
Adjustable dumbbells come in the form of short bars, which can be combined with weight plates to achieve any desired weight or in the form of adjustable dumbbells with 'dial-in' mechanism.
Over time, friction between treadmill belt and treadmill deck increases, requiring more force from the motor and increasing the stress on the treadmill in general. This leads to larger wear and tear of the treadmill and often very costly repairs.
Regular lubrication of the treadmill belt significantly reduces required motor force and stress on the treadmill and can prolong its operating time significantly.
When using and storing treadmills, it is important to protect the environment and treadmills from damage and to improve the workout sessions in as many ways as possible. Good treadmill mats dampen vibrations and noise and protect floor from the treadmill's weight, dripping lubricant, vibrations and similar. On the other hand, good mat protect treadmill from carpet and similar fibers entering into treadmills and damaging the motor, belt and other treadmill's components.
Ankle and wrist weights are small weights which increase resistance during physical activities like walking, running, rope jumping and similar. They help one to increase strength, stamina, calories burned and similar, but they also increase stress on joints, muscles and cardiovascular system.