This is a relatively new trend in exercise. Instead of plodding along
for a long time, this alternates "plodding along" with high intensity
exercise. This paper is about a "speed up" replacing an "All out maximum
effort" - the more traditional HIT method.

Of course, for people with chronic joint problems, it may not be good to
put an "All Out Effort" or even a "Speed Up" on those particular joints.
As you think about it, some of the traditional manual jobs people held
might have been a little like (modified) High Intensity Work. Maybe our
old style of life was pretty darned good for us - at least sometimes.

Science News

(Modified) High-Intensity Interval Training Is Time-Efficient and
Effective, Study Suggests

ScienceDaily (Mar. 12, 2010) — The usual excuse of "lack of time" for
not doing enough exercise is blown away by new research published in The
Journal of Physiology.
The study, from scientists at Canada's McMaster University, adds to the
growing evidence for the benefits of short term high-intensity interval
training (HIT) as a time-efficient but safe alternative to traditional
types of moderate long term exercise. Astonishingly, it is possible to
get more by doing less!

"We have shown that interval training does not have to be 'all out' in
order to be effective," says Professor Martin Gibala. "Doing 10
one-minute sprints on a standard stationary bike with about one minute
of rest in between, three times a week, works as well in improving
muscle as many hours of conventional long-term biking less strenuously."

HIT means doing a number of short bursts of intense exercise with short
recovery breaks in between. The authors have already shown with young
healthy college students that this produces the same physical benefits
as conventional long duration endurance training despite taking much
less time (and amazingly, actually doing less exercise!) However, their
previous work used a relatively extreme set-up that involved "all out"
pedaling on a specialized laboratory bicycle. The new study used a
standard stationary bicycle and a workload which was still above most
people's comfort zone -about 95% of maximal heart rate -- but only about
half of what can be achieved when people sprint at an all-out pace.

This less extreme HIT method may work well for people (the older, less
fit, and slightly overweight among us) whose doctors might have worries
about them exercising "all-out." We have known for years that repeated
moderate long-term exercise tunes up fuel and oxygen delivery to muscles
and aids the removal of waste products. Exercise also improves the way
muscles use the oxygen to burn the fuel in mitochondria, the microscopic
power station of cells.

Running or cycling for hours a week widens the network of vessels
supplying muscle cells and also boosts the numbers of mitochondria in
them so that a person can carry out activities of daily living more
effectively and without strain, and crucially with less risk of a heart
attack, stroke or diabetes.

But the traditional approach to exercise is time consuming. Martin
Gibala and his team have shown that the same results can be obtained in
far less time with brief spurts of higher-intensity exercise.

To achieve the study's equivalent results by endurance training you'd
need to complete over 10 hours of continuous moderate bicycling exercise
over a two-week period.

The "secret" to why HIT is so effective is unclear. However, the study
by Gibala and co-workers also provides insight into the molecular
signals that regulate muscle adaptation to interval training. It appears
that HIT stimulates many of the same cellular pathways that are
responsible for the beneficial effects we associate with endurance training.

The upside of doing more exercise is well-known, but a big question for
most people thinking of getting fit is: "How much time out of my busy
life do I need to spend to get the perks?"

Martin Gibala says "no time to exercise" is not an excuse now that HIT
can be tailored for the average adult. "While still a demanding form of
training," Gibala adds, "the exercise protocol we used should be
possible to do by the general public and you don't need more than an
average exercise bike."

The McMaster team's future research will examine whether HIT can bring
health benefits to people who are overweight or who have metabolic
diseases like diabetes.

As the evidence for HIT continues to grow, a new frontier in the fitness
field emerges.

Story Source:

    Adapted from materials provided by Wiley - Blackwell, via AlphaGalileo.

Journal Reference:

   1. Jonathan P Little, Adeel S Safdar, Geoffrey P Wilkin, Mark a
Tarnopolsky, and Martin J Gibala. A practical model of low-volume
high-intensity interval training induces mitochondrial biogenesis in
human skeletal muscle: potential mechanisms. The Journal of Physiology,
2010; DOI: 10.1113/jphysiol.2009.181743
http://dx.doi.org/10.1113/jphysiol.2009.181743

Free Abstract at the above link.

============================= ABSTRACT ============================

A practical model of low-volume high-intensity interval training induces
mitochondrial biogenesis in human skeletal muscle: potential mechanisms

   1. Jonathan P Little1,
   2. Adeel S Safdar1,
   3. Geoffrey P Wilkin1,
   4. Mark A Tarnopolsky2 and
   5. Martin J Gibala1,3

+ Author Affiliations

   1.
      1 McMaster University;
   2.
      2 McMaster University Medical Center

   1. * Corresponding author; email: gibalam@mcmaster.ca

Abstract

High-intensity interval training (HIT) induces skeletal muscle metabolic
and performance adaptations that resemble traditional endurance training
despite a low total exercise volume. Most HIT studies have employed "all
out", variable-load exercise interventions (e.g., repeated Wingate
Tests) that may not be safe, practical and/or well tolerated by certain
individuals. Our purpose was to determine the performance, metabolic and
molecular adaptations to a more practical model of low-volume HIT. Seven
men (21±0.4 yr, VO2peak = 46±2 ml·kg-1[middot]min-1) performed 6
training sessions over 2 wk. Each session consisted of 8-12 x 60 s
intervals at ≈100% of peak power output elicited during a ramp VO2 peak
test (355±10 W) separated by 75 s of rest. Training increased exercise
capacity, as assessed by significant improvements on both 50 kJ and 750
kJ cycling time trials (p<0.05 for both). Skeletal muscle (vastus
lateralis) biopsy samples obtained before and after training revealed
increased maximal activity of citrate synthase (CS) and cytochrome c
oxidase (COX) as well as total protein content of CS, COX subunits -II
and -IV, and the mitochondrial transcription factor A (Tfam) (p<0.05 for
all). Nuclear abundance of PGC-1α was ~25% higher after training
(p<0.05), however total PGC-1α protein content remained unchanged. Total
SIRT1 content, a proposed activator of PGC-1α and mitochondrial
biogenesis, was increased by ~56% following training (p<0.05). Training
also increased resting muscle glycogen and total GLUT4 protein content
(both p<0.05). This study demonstrates that a practical model of low
volume HIT is a potent stimulus for increasing skeletal muscle
mitochondrial capacity and improving exercise performance. The results
also suggest that increases in SIRT1, nuclear PGC-1α, and Tfam may be
involved in coordinating mitochondrial adaptations in response to HIT in
human skeletal muscle.