seconds should be performed corresponds
to your best 50-second interval pace, which
can, in theory, be tested in the warm-up for
each session. The final six minutes would be
spent cooling down from the 4-minute bout.
As this is a single 4-minute block, Tabata
Intervals are performed much more intensely
than traditional short intervals: Tabata uses
170% of vVO2max (the minimum velocity at
which VO2max occurs), whereas most short
interval sessions are performed around 95-
120% vVO2max, due to the longer duration
of the blocks and sessions.
Long Intervals
Long Interval protocols are the bread and
butter quality sessions of the endurance
world. They involve work duration bouts
of 3-8 minutes at intensities just under
one’s best aerobic maximum (p/vVO2max),
corresponding to an intensity of between
90-95% of HRmax, with short recovery
periods of 1-2 minutes. This type of training
allows one to accumulate an impressive
amount of time at, or close to, VO2max in the
session. For this reason, Long Intervals are
the primary interval of choice for endurance
athletes.
Four commonly performed long interval
sessions are:
• 6 x 3 minutes with 2 minutes recovery
• 5 x 4 minutes with 60 seconds recovery
• 4 x 6 minutes with 2-minutes recovery
• 10 x 1 minute with 60 seconds recovery.
Although this session has an interval work
bout of less than the defined duration for
long intervals, the accumulated session load
is similar, so most people categorise this
session type as a long interval workout.
Targets of interval training
Paul Laursen and Martin Bucheit, in their
marvellous and definitive textbook on
interval training, Science and Application of
High-Intensity Interval Training, recommend
that interval training should be categorised
into the three primary physiological targets
12 weeks of sprint interval training improved
indices of cardiometabolic health similar to
traditional endurance training despite a five-fold
lower exercise volume and time commitment
42 | NETWORK SPRING 2019
of each session, namely, the anaerobic,
aerobic or neuromuscular systems. Based
on this, Laursen and Bucheit further break
these down into six subtypes of interval
training:
• Type 1 targets the aerobic system only
• Type 2 elicits both an aerobic response
and demands an input from the
neuromuscular system
• Type 3 challenges the aerobic and
anaerobic system
• Type 4 hits all three physiological targets
(aerobic, anaerobic and neuromuscular)
• Type 5 turns off the oxidative system and
exclusively targets the anaerobic and
neuromuscular systems
• Type 6 is a neuromuscular only type of
training response.
Knowing the types of each interval method
allows the trainer or coach to design
more specific training programs for their
athletes to improve performance in a
specific situation. For example, training for
a marathon or Ironman triathlon would see
intervals largely targeting a Type 1 response,
whereas a 6-minute Strava KOM (cycle
challenge) would be best trained using
intervals targeting a Type 3 or 4 response.
The health benefits of HIIT
Several decades of research has shown
that interval training is at least equivalent
to, and in some instances more effective
than,
moderate
intensity
continuous
aerobic exercise at improving markers
of cardiometabolic health. HIIT has been
shown to improve mitochondrial function,
insulin sensitivity, glucose control, lipid
metabolism and blood pressure.
Leading researcher in this field, Martin
Gibala, has recently stated that there is now
a considerable body of evidence suggesting
that high-intensity interval training can elicit
cardiometabolic health benefits comparable
or superior to traditional endurance training,
despite reduced time commitment. This is
evidenced by a recent systematic review
and meta-analyses based on 65 intervention
studies that concluded, ‘HIIT may serve as a
time-efficient substitute or as a compliment
to commonly recommended moderate
intensity continuous exercise in improving
cardiometabolic health’.
Gibala’s team found that a single session
of interval training involving 10 × 1-minute
cycling bouts at 90% maximal heart rate
elicited larger and longer-lasting reductions
in 24-hour postprandial glycemia in obese
adults, than a 30-minute bout of moderate
exercise at 65% HRmax that was matched
for total external work. Other studies have