Page 113 - Journal of Special Operations Medicine - Summer 2015

two provided equal improvements in physical fitness. Table 1 Measures of External and Internal Load
This highlights that it is the total training load com- External Load Internal Load
pleted in a cycle of training that is key for improving
physical performance in SOF and shows training load Power meter Rate of perceived effort
Speed
Heart rate
periodization is a method proven to work for SOF. 6
Force Questionnaires/diaries
Accelerometers Hormonal status
One important feature of the training load method is the Jumping
ability to modify an individual’s training within a team Measurable Descriptors
setting. Much like team sport athletes, SOF personnel
7
must operate and train as a unit; however, within a unit, Frequency, intensity, duration
a wide range of physical characteristics exist. As dem- Maximum, minimum, average
onstrated in team sports, age, fitness, experience, and Number of efforts, repetitions, sets
Baseline, before, after, peak
player position significantly impact the individual train- Modality
ing load experienced during training. Thus, some in- Environment
7–9
dividuals on a team are at greater risk of injury and may
fail to respond positively to training if it is not tailored
to individual needs. Monitoring the response to training Ideally, external load should be measured to the greatest
can help an Operator determine which training factors extent possible in the universal measurement of power,
should be modified so they can achieve mission-specific which can account for differences in body weight, type
performance goals without accumulated fatigue. of training, and training terrain. Power meters are read-
ily available for training physical activities such as cy-
cling, rowing, swimming, and stationery skiing. Until
Training Quantification Toolbox
recently, measuring power when walking or running was
As technology continues to emerge, multiple devices are not possible, yet this is the form of external load most
available on the market to quantify training load. The commonly performed by SOF. However, recently, a de-
training load consists of both external and internal units vice called Stryde has been developed to measure power
of load. 10,11 When choosing a tool to monitor external while running or walking; released in summer 2015.
and internal load, it is important to ensure it is capable This should allow for a more universal use of power as
of detecting changes in physical fitness and measuring an external load measure by SOF. Other devices, includ-
the intensity of each training stress performed by the ing GPS, accelerometers, and/or gyroscopes, can also be
Operator. Understanding the relationships between ex- used for running or walking activities but do not provide
ternal and internal loads can assist SOF in creating train- a power measure. 10,11 Measures of external load should
ing that allows them to achieve the desired improvement be examined by distribution (e.g., 10 repetitions of
in performance without high levels of fatigue. 200W of power for 2 minutes during a 60-minute train-
ing session) of power, speed, or accelerometer counts for
A summary of tools with a scientific basis for quanti- each training session. Monitoring how measures of ex-
17
fying training load is presented in Table 1. All of the ternal load are distributed can be accomplished through
tools listed in the table and described here can measure use of an application (“app”) downloaded to a smart-
changes in training intensity and, as a result, can be phone or smartwatch, and then used with sport watches
placed into training zones, which will allow Operators or accelerometers such as a Garmin, Epson’s Runsense,
to compare the intensity between different types of train- Fitbit, or Nike Fuelband.
ing. 2,12 Training zones are based on an individual’s abil-
ity to train at a given intensity level. A more-detailed Internal load is a function of an individual’s perception
13
description of devices for measuring training intensity and awareness of the stress experienced during training
by external and internal load is provided here. 6 and recovery. Methods for monitoring internal load
18
can range from simplistic measures—rate of perceived
External load can be defined as the “amount of work effort (RPE), heart rate (HR), diaries, and sleep—to ad-
the body has completed.” The ability to perform work vanced measures such as hormone concentrations. RPE
is dependent on an individual’s characteristics such as is commonly used to assess internal load given its ease
age, gender, genetics, and physical characteristics in- of use and strong relationship with other measures of in-
cluding body weight, muscle mass, and leg length and ternal load. It is the form of internal load monitor most
girth (thigh, calf, waist, etc.). 8,9,14–16 Measures of exter- commonly used by Operators to perform missions and,
nal load include power, speed, acceleration, decelera- as a result, should also guide training intensity. RPE
tion, and jumping. Tools for monitoring external load determines internal load through a score that asks an
include power meters, accelerometers, gyroscopes, and individual to integrate the physical and psychological
global positioning systems (GPS). stress they experience in training. 19,20 Because RPE takes

Monitoring Training for Human Performance Optimization 103