Strength Training & Cardiovascular Training Side By Side: How Does One Affect the Other?

Designing an ideal strength training program for sport in itself can be a complex process. Yet resistance training is only one component of an athlete's overall training regime, which can also include endurance training, speed training, flexibility training and skill / tactical work.

Perhaps the most important element in a total conditioning program is adequate rest and recovery, without which the body cannot adapt properly to the imposed demands.

How does strength training interact with other components of fitness? Does endurance training have a negative effect on strength and power? And does strength and power training negatively effect aerobic power or flexibility?

This article examines the integration of a sport-specific strength training plan into the total conditioning program and how any negative impact of concurrent training can be reduced.

Concurrent Strength & Endurance Training: Effect on Strength

The body adapts specifically to the demands imposed upon it. So what happens when two different modes of training that place different stresses on the body are performed concurrently?

A number of studies have examined the compatibility of simultaneous strength and endurance training (2,3,4,5). In 1980, Hickson (4) found that strength development maybe negatively effected by endurance training. Hunter and co-workers found that over a 12-week period a program of barbell squats only increased leg strength by 39%. This compared favourably to a program of squats and endurance training, which increased strength by just 24% (6).

Similar detriments to strength have been supported by other researchers (7,8). In contrast however, studies have also found that endurance training has no detrimental effect on strength development (9,10,11,12,13). Interestingly, although some of these studies found a negative effect on strength and some didn't, all agreed that concurrent strength and endurance training has no negative effect on endurance.

Strength at high velocities may be more vulnerable to endurance training than strength at slow speeds (5,7,13). This has obvious implications for power and speed performance which may be susceptible if a significant amount of endurance training is undertaken.

Kraemer and fleck (1) suggest that strength and endurance training programs with a moderate amount of volume seem to be compatible with no deleterious effects on either strength or endurance. As the volume increases to that adopted by elite athletes, detriments in strength are more likely to occur. It may be the overtraining phenomenon that is to blame rather than the incompatibility of concurrent strength and endurance training.

Concurrent Strength & Endurance Training: Effect on Endurance

Beginning in the 1970's many runners avoided resistance training for fear that it resulted in a decrease in endurance performance. This was based on studies that found a reduction in mitochondrial density following a resistance training program (14).

Subsequent research has found that strength training does not reduce endurance performance (7,8,9,10,11,12) and mitochondrial density can actually increase as a result of a resistance training program (15).

There is evidence to suggest that strength training is beneficial to endurance performance (16,17,18) in non-athletes. For example, time to exhaustion in a cycle ergometer test and lactate threshold can be increased without any change in VO2max (18).

Strength training may also improve endurance performance in trained athletes. In one study on elite cyclists, 30-second sprint performance decreased with heavy endurance training. By adding resistance training to the program, sprint performance was maintained without any negative effects on endurance (19). Additionally, by substituting 32% of total endurance training in elite distance runners for strength training, 5km performance has been improved significantly (20).

In summary, substantial endurance training may be detrimental to strength and power athletes. In endurance sports, strength training applied correctly appears to have an ergogenic effect without altering VO2max.

Strength Training & Flexibility

The flexibility training section of the site discuses the effect of stretching as part of the warm up. Recent research has found that pnf stretching can hinder vertical jump performance (21). Static stretching may also be detrimental to subsequent power performance (22,23).

These post-stretch decreases in force production may be related to the inactivation of the muscles affected - more so than a change in elasticity often thought to be the cause (24). Evidence that static or pnf stretching immediately prior to power and speed events harms performance is by no means conclusive and studies have also shown it to have no negative effects. The general consensus seems to favor dynamic stretching as part of the warm up and static stretching following exercise or a training session. While the debate continues, how do the long-term adaptations associated with strength training affect flexibility?

One study measuring the effects of 11 weeks of resistance training on range of movement found that ankle dorsiflexion and shoulder rotation both increased without any flexibility training (25). Research in the elderly has found that resistance training alone can in increase performance in the sit and reach test by 13% (26).

While these increases in range of motion can be quite marked in sedentary individuals, the effect of strength conditioning on flexibility in trained individuals is less pronounced. For example, weightlifters posses average to above average flexibility in most joints (27,28,29). This would suggest that long-term physiological changes that occur through lifting weights neither significantly increase nor reduce range of motion.

For athletes, perhaps more important than the extent of flexibility is the ability to control movements within a given range of motion. For example, a martial artist may be able to kick to head height but lack any significant power or control at that joint angle. Strength training and concurrent flexibility training can help to control movements within an athlete's current range of movement (30).


1) Fleck SJ and Kraemer WJ. (2004) Designing Resistance Training Programs, 3rd Edition. Champaign,IL: Human Kinetics

2) Chromiak JA and Mulvaney DR. A review: The effects of combined strength and endurance training on strength development. J Appl. Sport Sci. Res. 1990 4:55-60

3) Dudley GA, Fleck SJ. Strength and endurance training. Are they mutually exclusive? Sports Med. 1987 Mar-Apr;4(2):79-85

4) Hickson RC. Interference of strength development by simultaneously training for strength and endurance. Eur J Appl Physiol Occup Physiol. 1980;45(2-3):255-63

5) Dudley GA, Djamil R. Incompatibility of endurance- and strength-training modes of exercise. J Appl Physiol. 1985 Nov;59(5):1446-51

6) Hunter G, Demment R, Miller D. Development of strength and maximum oxygen uptake during simultaneous training for strength and endurance. J Sports Med Phys Fitness. 1987 Sep;27(3):269-75

7) Hennessy LC, Watson AWS. The interference effects of training for strength and endurance simultaneously. 1994 15:326-31

8) Nelson AG, Arnall DA, Loy SF, Silvester LJ, Conlee RK. Consequences of combining strength and endurance training regimens. Phys Ther. 1990 May;70(5):287-94

9) Bell GJ, Petersen SR, Wessel J, Bagnall K, Quinney HA. Physiological adaptations to concurrent endurance training and low velocity resistance training. Int J Sports Med. 1991 Aug;12(4):384-90

10) Hortobagyi T, Katch FI, Lachance PF. Effects of simultaneous training for strength and endurance on upper and lower body strength and running performance. J Sports Med Phys Fitness. 1991 Mar;31(1):20-30

11) Sale DG, MacDougall JD, Jacobs I, Garner S. Interaction between concurrent strength and endurance training. J Appl Physiol. 1990 Jan;68(1):260-70

12) McCarthy JP, Agre JC, Graf BK, Pozniak MA, Vailas AC. Compatibility of adaptive responses with combining strength and endurance training. Med Sci Sports Exerc. 1995 Mar;27(3):429-36

13) Kraemer WJ, Patton JF, Gordon SE, Harman EA, Deschenes MR, Reynolds K, Newton RU, Triplett NT, Dziados JE. Compatibility of high-intensity strength and endurance training on hormonal and skeletal muscle adaptations. J Appl Physiol. 1995 Mar;78(3):976-89

14) MacDougall JD, Sale DG, Moroz JR, Elder GC, Sutton JR, Howald H. Mitochondrial volume density in human skeletal muscle following heavy resistance training. Med Sci Sports. 1979 Summer;11(2):164-6

15) Chilibeck PD, Syrotuik DG, Bell GJ. The effect of concurrent endurance and strength training on quantitative estimates of subsarcolemmal and intermyofibrillar mitochondria. Int J Sports Med. 2002 Jan;23(1):33-9

16) Hickson RC, Rosenkoetter MA, Brown MM. Strength training effects on aerobic power and short-term endurance. Med Sci Sports Exerc. 1980;12(5):336-9

17) Hickson RC, Dvorak BA, Gorostiaga EM, Kurowski TT, Foster C. Potential for strength and endurance training to amplify endurance performance. J Appl Physiol. 1988 Nov;65(5):2285-90

18) Marcinik EJ, Potts J, Schlabach G, Will S, Dawson P, Hurley BF. Effects of strength training on lactate threshold and endurance performance. Med Sci Sports Exerc. 1991 Jun;23(6):739-43

19) Bastiaans JJ, van Diemen AB, Veneberg T, Jeukendrup AE. The effects of replacing a portion of endurance training by explosive strength training on performance in trained cyclists. Eur J Appl Physiol. 2001 Nov;86(1):79-84

20) Paavolainen L, Hakkinen K, Hamalainen I, Nummela A, Rusko H. Explosive-strength training improves 5-km running time by improving running economy and muscle power. J Appl Physiol. 1999 May;86(5):1527-33

21) Church JB, Wiggins MS, Moode FM, Crist R. Effect of warm-up and flexibility treatments on vertical jump performance. J Strength Cond Res. 2001 Aug;15(3):332-6

22) Nelson AG, Guillory IK, Cornwell C, Kokkonen J. Inhibition of maximal voluntary isokinetic torque production following stretching is velocity-specific. J Strength Cond Res. 2001 May;15(2):241-6

23) Young W, Elliott S. Acute effects of static stretching, proprioceptive neuromuscular facilitation stretching, and maximum voluntary contractions on explosive force production and jumping performance. Res Q Exerc Sport. 2001 Sep;72(3):273-9

24) Behm DG, Button DC, Butt JC. Factors affecting force loss with prolonged stretching. Can J Appl Physiol. 2001 Jun;26(3):261-72

25) Thrash K, Kelly B. Flexibility and strength training. J Appl. Sports Sci. Res. 1987 1:74-75

26) Barbosa AR, Santarem JM, Filho WJ, Marucci Mde F. Effects of resistance training on the sit-and-reach test in elderly women. J Strength Cond Res. 2002 Feb;16(1):14-8

27) Beedle B, Jesse C and Stone MH. Flexibility characteristics among athletes who weight train. . J Appl. Sports Sci. Res. J appl Sports Sci Res. 5: 150-154

28) Leighton JR. Flexibility characteristics of three specialized skill groups of champion athletes. Arch Phys Med Rehabil. 1957 Sep;38(9):580-3

29) Jenson C and Fisher G. 1979. Scientific basis of athletic conditioning. Philadelphia: Lea & Febiger

30) Stadler MA, Noble BJ, Wilkerson JG. The effects of supplemental weight training for ballet. 1990 4:94-102