Dr. Squat - Dr. Fred Hatfield

From Designing Resistance Training Programs, 3rd Edition, by Steven J. Fleck and William J. Kraemer, pp. 134-135:

Concurrent Strength and Endurance Training

Training adaptations are specific to the imposed training stimulus. So, how compatible are two different types of training that result in different adaptations when both types of training are performed concurrently? Our understanding of exercise compatibility primarily relates to the concurrent use of aerobic endurance and strength training programs (Chromiak and Mulvaney 1990; Dudley and Fleck 1987). Studies examining such concurrent training provide the following conclusions.

* High-intensity endurance training may compromise strength, especially at high velocities of muscle actions.
* Power capabilities may be most affected by the performance of both strength and endurance training.
* High-intensity endurance training may negatively affect short-term anaerobic performance.
* The development of peak oxygen consumption is not compromised by a heavy resistance training program.
* Strength training does not negatively affect endurance capabilities.
* Strength and power training programs may benefit endurance performances by preventing injuries, increasing lactic acid threshold, and reducing the ground contact time during running.

The topic of exercise compatibility came to the attention of the sport science community when Hickson (1980) demonstrated that the development of dynamic strength may be compromised by concurrent performance of both resistance and endurance training. This study lasted only eight weeks, so whether the reduction of strength development would continue over a long training period was unknown. Because no periodization of either the resistance or the endurance training was used, and a relatively high training volume was performed, overtraining may have occurred in the group that performed both types of training simultaneously. Conversely, in the group training for strength and endurance, improvement in aerobic capacity was not compromised compared to the group performing only endurance training.

Five years later Dudley and Dmajil (1985) used a more conventional frequency of training and found only decrements in the magnitude of increase in angle-specific peak torque at fast velocities (160-278 degrees · sec-1) of movement in a group simultaneously trained for strength and endurance as compared to a group trained only for strength. No decrements in angle-specific peak torque were observed at slow velocities (48-96 degrees · sec-1) of movement in the group that simultaneously trained for strength and endurance. This study was the first investigation to suggest that power may in fact be first affected by concurrent training over a short training period. Again, aerobic power of the combination training group was not compromised compared to a group trained for endurance only. These conclusions were supported by Hunter, Demmett, and Miller (1987), who examined simultaneous resistance training and endurance training over twelve weeks. Barbell squats were emphasized in this training program. An increase in strength of 39% was observed in the strength-only group, and the combined group increased by 24%. No impairment of peak oxygen consumption was observed, but strength at high velocities of movement was compromised in the endurance training group.

These studies sparked an interest in the physiological compatibility of simultaneous strength and endurance training. Using various experimental protocols to explore adaptational responses to concurrent strength and endurance training, studies have shown that strength can be either compromised (Hennessy and Watson 1994; Nelson et al. 1990) or unaffected (Bell et al. 1991b; Hortobagyi, Katch and LaChance 1991; Sale et al. 1990), whereas endurance capabilities are not affected. Other studies have reported that both strength and endurance capabilities can be attenuated especially over longer periods of concurrent training in trained athletes (Hennessy and Watson 1994; Nelson et al. 1990). Hennessy and Watson (1994) clearly demonstrated that strength, power, and speed performance may be most susceptible to “incompatibility” because of the high intensity and volume trained by highly trained athletes.

McCarthy and colleagues (1995) examined the effect of simultaneous strength and endurance training using a more realistic and typical 3-days-a-week routine. The strength training program consisted of four sets of 5 to 7 repetitions for eight exercises, and the endurance protocol consisted of 50 minutes of cycle exercises at 70% of heart rate reserve. A strength-only group, endurance-only group, and combined group trained for 10 weeks. Subjects who performed the strength-only training or both types of training increased their 1RM squat, bench press, vertical jump, and maximal isometric knee-extension strength as well as their fat-free mass. The endurance group demonstrated no change in these variables, but did increase peak oxygen consumption, as did the combined training group. The results of this study show that conventional training frequencies and programs are in fact compatible and further indicate that “overtraining” may be the ultimate cause of exercise incompatibility. Thus, whether concurrent strength and endurance training are compatible may depend on many factors such as training status, training intensity, and training volume.

Almost all of the studies used men as subjects, and only limited amounts of data are available on this issue in women. But in a study by Volpe and colleagues (1993) previously sedentary college aged women used conventional strength training (a periodized program) and endurance training (75% of predicted maximal heart rate) programs for 3 days per week over 9 weeks, and no incompatibility was observed for strength or endurance performances. One interpretation of these results is that training status does affect whether concurrent training is incompatible.

(Note: Designing Resistance Training Programs further discusses issues pertaining to concurrent training on pp. 135-138)

Smitty, it's a quite from Fleck and Kraemer's book.

Doc, you need to check the censored words list in your admin control panel...seems like "fle c k" and "sh o rt" were censored so the computer changes these words automatically into other words.

I also had some inadvertant censoring on a post. Couldn't figure out what the heck was happening, glad I'm not crazy

Sorry guys, fixed it!