Everyone has experienced showing up at the doctor’s office and being tasked with sitting very still while vital signs are taken. You sit almost trance-like, concentrating on slowing your heartbeat, willing your blood pressure down, avoiding any sudden movement that might affect the signals being monitored for posterity. It’s quite another matter when body signals are being monitored and measured from someone in full motion, particularly an elite athlete, all systems performing at maximum capacity. How are multiple facets of our physiology accurately captured when we are puffing and sweating at full exertion? Don’t these movements introduce artifact into the data and affect its quality? Won’t the result be an unusable mess? The truth is with proper setup and hardware, acquiring accurate signals from exercise physiology subjects has never been easier.
Signals typically and simultaneously acquired during exercise physiology studies are heartbeat (ECG), respiration (RSP), muscle activity (EMG), in addition to oxygen uptake, carbon dioxide production, blood pressure, core/surface temperature data, range of motion, and even GPS, if the participant is performing the activity outside the lab.
An important factor in exercise physiology studies is choosing the right electrodes, as well as their placement. We recommended using long-term electrodes, such as EL502, which can be worn up to 24 hours. If sweat is a problem, use stress electrodes which adhere better and are resistant to moisture. For even better adhesion to contoured parts of the body, use fabric electrodes. It is also important to prep the electrode site correctly, by first abrading the skin using an ELPAD, and making sure the electrode has sufficient conductive gel.
For measuring ECG signals, particularly Lead II, place the electrodes over bone such as a clavicle or rib to minimize movement artifact. For studies involving a lot of abdominal movement, a Lead I ECG configuration is recommended (left and right clavicle placement). This will help assure a good ECG signal during exercise.
If the participant is inside the lab (say, on a treadmill or exercise bike), a “wired” system, such as BIOPAC’s MP160 System with 100D-Series Smart Amplifiers is a good choice. Up to 16 channels of data can be acquired which can be extended to include 16 calculation channels of derived signals or online filters. For more freedom of movement, the MP160 System with BioNomadix wireless transmitters/receivers offer unrestrained comfort, including a BioShirt with built-in ECG fabric electrodes and RSP transducer. The wireless BioNomadix System has a range of 10 meters line-of-sight between transmitters and receivers. For long-term studies outside the lab, the BioNomadix Logger records and logs data for up to 24 hours while the subject goes about their protocol.
An additional wireless system commonly used for exercise studies is the Mobita System. Mobita is wireless, and like the aforementioned systems, works with the MP160 and AcqKnowledge software for recording and advanced analysis. Mobita is compact enough to fit in your hand and will record up to 32 channels of biopotential data.
No reason to keep still or be quiet any longer. With this many choices, acquiring high-quality exercise physiology data over a full range of body signals is within easy reach.
For more information about exercise physiology and how to maximize your results, we invite you to view our free webinar, Recording Great Data from Exercising and Mobile Subjects.