Sports Medicine: Just the Facts

CHAPTER 8 • BASICS IN EXERCISE PHYSIOLOGY 45

DELAYED-ONSETMUSCLESORENESS

• Delayed-onset muscle soreness (DOMS) is a term
  used to describe temporary soreness that results pri-
  marily from eccentric exercise and resistance training.
  It is usually noted the day after the exercise and may
  last 3 to 4 days.
  •Factors that may elicit DOMS inflammation, osmotic
  changes within muscle tissue, microtrauma to the
  tissue, and/or alterations in calcium metabolism.

PLYOMETRICS

• Plyometrics is a specific method of training for power
  or explosiveness. Most plyometric exercises involve
  jumping, bounding, and hopping. The force generated
  by a lengthening contraction (eccentric) can be
  markedly increased if it is followed by a shortening
  contraction (concentric).


• Plyometric training is a process that specifically
  focuses on rapid pairing of eccentric and concentric
  contractions, or stretch/shortening cycles, to produce
  increases in power.

EXERCISE TRAINING

PRINCIPLES OF TRAINING

• FITT:This is an acronym to describe a physical train-
  ing variable that can be altered to achieve various fit-
  ness goals. FITT stands for frequency, intensity, time
  (duration), and typeof exercise.


• Overload: The overload principle states that gains in
  strength/endurance come about only when progres-
  sively greater demands are placed on the cardiopul-
  monary and musculoskeletal systems.


• Periodization: This is a technique that involves alter-
  ing training variables (repetitions/set, exercises per-
  formed, volume, and rest interval between sets) to
  achieve well-defined gains in muscular strength,
  endurance, and overall performance for a specific
  event. The specific phases include activation (getting
  the body ready for a new activity–about 4 weeks), fol-
  lowed by strength development (4 to 7 weeks) and
  then muscular endurance (8 to 12 weeks).


• Quantifying exercise intensity: Exercise intensity
  can be estimated from METs, a percentage of maximal
  HR, a percentage of VO2max, or as a function of RPE.


• Absolute and relative intensity: If two individuals (Tom
  and Mark) have VO2maxvalues of 4.2 and 3.2 L/min
  respectively, and both work at 2.5 L/min, then they
  would be working at the same absolute power output,
  but at different relative intensities because they have

different VO2max values. Tom would be working at

2.5/4.2 or 60% and Mark at 2.5/3.2 or 78% of VO2max.

ADAPTATIONS TO TRAINING

ENDURANCETRAINING

• Adaptations to endurance exercise include improve-
  ments in neuromuscular and cardiovascular function
  and in respiratory muscle efficiency and cost of
  breathing; decreases in body mass/body fat; improve-
  ments in heat tolerance; increases in self-esteem;
  lower blood lactate accumulation at higher power out-
  puts, and increased insulin sensitivity.

RESISTANCETRAINING

• Resistance training induces a variety of adaptations,
  with clear increases in strength. Neural adaptations
  include increases in strength with/without hypertrophy,
  greater synchronicity in activating motor units, and
  increased presynaptic and postsynaptic neurotransmit-
  ter receptors. Contractile adaptations include muscle
  hypertrophy within the whole muscle and myofibers
  through increased synthesis and accretion of intracellu-
  lar myofibrilar proteins and activation of local satellite
  cells to add new nuclei to existing myofibers.


• Fiber type specific adaptations induced by resistance
  training depend on volume and intensity, but a
  common change is an increase in the percentage of
  Type IIa fibers, at the expense of the Type IId(x/b)
  fibers. Resistance training is not usually associated
  with increases in VO2max, but may enhance overall car-
  diovascular function by improving strength that
  lessens the load of daily activities.

ESTIMATING STRENGTH

AND ENDURANCE

AEROBIC AND ANAEROBIC POWER

• Simple in-office and field tests can be used to estimate
  VO2max. These include the 2-mi run, 12-min run, and
  the 3-min step test. Other tests include submaximal
  cycle ergometry. Tests for anaerobic power include
  vertical jumps, the Wingate anaerobic cycle test, a
  running-based anaerobic sprint test (400 m), and the
  300-yd shuttle run.

MUSCULAR STRENGTH AND ENDURANCE

•Tests to assess muscular strength include free wei-

ghts (1 RM: back squats/bench presses), hand grip