The basics of exercise selection, structure and sequence need to be understood to maximize a programís potential. Studies have shown that the order exercises are executed significantly affects strength performance. If strength and muscle growth is the goal, large multiple-joint movements should be performed early in the training session, when fatigue is minimal. The sequencing of exercises might not be as important for endurance training since fatigue is a necessary component. For that reason, building muscular endurance allows more freedom in scheduling workout variations than strength-building programs.

Warm up but donít burn

Warming up prior to training can improve performance. However, there is a threshold to respect; a point when performance is negatively impacted. Increases in body temperature speed up chemical reactions. Based on biochemical research, 50-degree Fahrenheit increases in tissue temperatures can double the speed of bodily processes. Obviously, an elevation of this nature would not be possible in a human body, since the organism could not survive such a high internal temperature.

A moderate increase in body temperature is best for improving muscular contractions and related metabolic reactions. A study dated back to 1945 demonstrated that anaerobic exercise performance improves by roughly five percent for each degree the muscleís temperature is increased. In contrast, excessive elevation of the core temperature impairs performance, primarily related to changes in the central nervous system that result in central fatigue. Hyperthermia can also impair cardiovascular function, causing reduced arterial oxygen delivery and limited efficiency of the aerobic energy systems.

Several studies indicate that a peak internal temperature exists where a person will stop voluntarily exercising. This effect is tightly connected to core temperature and not local muscle temperature. A core temperature of 100 degrees Fahrenheit is considered a normal active state but may impair performance over long durations.

In March 2008, Lars Nybo published a study in the Journal of Applied Physiology to examine the effects of hyperthermia and fatigue. In his research, exercise on a bicycle was maintained for an hour at core temperatures of 100 degrees, without exhaustion. On the other hand, when core temperature stabilized at 104 degrees, fatigue resulted within 50 minutes. Researchers noted that untrained individuals will fatigue sooner than trained athletes. Competitive events can also delay fatigue due to the heightened motivation. Certain dietary supplements, such as caffeine and ephedrine, can also counteract feelings of fatigue at high core temperatures. Cases of hyperthermia, which can become life threatening, are often reported while training in a hot environment.

Based on current research, it seems evident that muscles must be warm for maximum performance but core temperatures must remain less than 104 degrees during activity. As core and brain temperatures eventually reach and exceed 100 degrees, central fatigue proceeds with a decrease in oxygen delivery to exercising muscles. Highly elevated brain temperatures can negatively affect neuromuscular function. Cardiac output declines and muscle blood flow decreases to a point that increased oxygen extraction cannot be made up by the limited oxygen delivery.

In well-trained strength athletes, intense exercise is associated with high rates of heat production in the muscles. Itís possible to increase core temperature to 104 degrees in less than 10 minutes in a warm environment. Allowing some passive recovery and staying well hydrated will support the bodyís cooling mechanisms. Itís important to warm up before exercise, but overdoing it can disable any possible ergogenic effects.

Thomas Kurz, author of Science of Sports Training: How to Plan and Control Training for Peak Performance, explains correct exercise sequences for daily training cycles. His theories serve to minimize overtraining probability. In a single workout, Kurz suggests technique before speed drills, but both before strength or endurance training. Speed or strength exercises should be performed before endurance efforts. Training otherwise will extend your recovery time to double or triple that of a properly sequenced workout.

High intensity anaerobic training (speed or strength exercises) after fatiguing aerobic efforts (endurance) produces more lactic acid than the reverse order. Excessive lactic acid taxes the bodyís ability to restore proper pH balance. Sodium is taken from body fluids and phosphorous from bones, causing demineralization and loss of calcium, required for optimal muscle contractions. Short-term fatigue from depletion of substrates, accumulation of metabolites and dehydration will limit the bodyís ability to exert itself at optimal intensities or durations.

Itís important to understand that each athlete is an individual with personal capabilities for physical output and adaptation. A training program that drives one athlete into severe overtraining syndrome may generate record-breaking performance in another.