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The Practical Scientist – Part IV

In the previous additions of The Practical Scientist I have reviewed Nutrition studies. In this addition I will take a look at a study that focuses on exercise. The purpose of this article is to focus on strength and power gains from either complete cessation of training (DTR) or a tapering period (TAP). The study I am reviewing here also investigated circulating anabolic/catabolic hormones, but we will only look at the effects on strength and power in this article.

Some Key points from Detraining and Tapering Effects on Hormonal Responses and Strength Performance by Izquierdo M and colleagues.

Periodized strength training typically incorporates a taper phase to reduce accumulated fatigue. It is believed that the taper enhances performance by allowing greater recovery. Short-term reduction of the strength training volume while the intensity is kept high is a well-known coaching practice used to peak performance. However, a marked reduction of training intensity and volume, or complete training cessation, could bring about a partial or complete loss of recently acquired training-induced increases.

Decreased strength performance (7-12%) has been shown after short-term periods (4-8 weeks) of training cessation or periods of reduced training. On the contrary, other studies have shown that previously untrained or recreationally trained athletes can maintain or suffer only a slightly decrement in their neuromuscular performance during short periods (2-3 weeks) of training cessation. Recently, Andersen et al. reported that 3 weeks of resistance training cessation led to increased velocity and power of maximal unloaded limb movement in previously untrained subjects but isokinetic maximal strength reverted to pretraining levels. After a period of tapering, moderately strength trained subjects improved low velocity isokinetic strength performance of the elbow flexors for at least 8 days. Gonzalez-Bandillo et al. examined the effect of 3 resistance training volumes and reported that short-term resistance training (10 weeks) using moderate volume tended to produce greater enhancements in strength performance compared with low and high training volumes of similar intensity in trained young weightlifters.

We hypothesized short-term (4 weeks) detraining after 16 weeks of resistance training in strength trained athletes would lead to a complete loss of recently acquired maximal strength and power gains, whereas a taper phase would lead to further increases in muscle strength and power. Forty-six physically active men were matched and randomly assigned to a TAP-tapering period (n=11), DTR- complete cessation of training (n=14), or control group (n=21), subsequent to a 16-week PRT program. Muscular and power testing and blood draws to determine basal hormonal concentrations were conducted before the initiation of training (T0), after 16 weeks of training (T1), and after 4 weeks of either DTR or TAP (T2). No significant differences were observed between groups at the beginning of the study for 1RM measurements (exercises measured were bench press and parallel squat). Significant increases were observed in 1RM bench press for TAP and DTR groups at T1 compared with T0. After the tapering period, 1RM bench press significantly increased (2%) at T1 to T2, whereas a significant decrease (-9%) was observed in the DTR group. No significant differences in 1RM bench press were observed in the control group during the study. No significant differences were observed between groups in muscle power output at 60% of 1 RM squat and 1RM bench press at the beginning of the study. Significant increases took place in muscle power output at 60% of 1RM bench press for TAP (29%) and DTR (26%) at T1 compared with T0. After the tapering period muscle power output in the bench press remained unaltered (1%) in the TAP group, whereas a significant decrease in muscle power output (-17%) was observed in DTR. After detraining, the magnitude of muscle power output decrement at 60% of 1RM bench press was greater than that recorded in TAP.

Significant increases took place in maximum concentric 1RM squat strength for the TAP and DTR groups at T1 (27% and 22%) and T2 (30% and 16%) compared with T0. After the tapering period (from T1 to T2) a significant increase (3%) was observed in TAP, whereas a significant decrease (-6%) was observed in DTR. Significant increases were observed in muscle power output at 60% of 1RM squat fro the TAP and DTR groups at T1 (37% and 29%) and T2 compared with T0. During the tapering period, no significant changes were observed for leg muscle power (3%) whereas a significant decrease were observed in DTR (-14%). No changes were observed in the control group.

Significant increments took place in the height in counter movement jump for TAP and DTR groups at T1 compared with T0. During TAP, the height in CMJ remained unaltered, whereas a significant decrease was observed in DTR (-3%).

My thoughts

This study indicates after 4 weeks of detraining we can expect reductions in maximal strength and muscle power output. We can also expect a more severe effect on power than maximal strength due to detraining. With a proper taper phase we can expect increases in maximal strength with little changes in power output. I would expect different results than the ones obtained in this study when comparing a 1-2 week taper vs. detraining phase. I think from a practical standpoint a shorter phase would be more applicable to most athletes. The majority of successful athletes I have worked with rarely detrain for more than two weeks. Although it is not uncommon to use tapering phase for four weeks or longer. There are many different exercise regimens used in tapering phases. The tapering phases I use in my programs depends on the individual as well as the sport. An important consideration when designing tapering phases is where does the competition fall relative previous competitions and up and coming competitions. A major finding with this study was that detraining resulted in a larger reduction in muscle power than maximal strength in the upper and lower extremities. Other studies have reported that vertical jump performance, isometric fast force production, and power during unloaded knee extension can be maintained or slightly increased over 3-6 weeks of detraining. In general I would suggest that detraining phases do not last longer than 2 weeks. I generally recommend tapering phases of 3-4 weeks. The exercise prescription depends on numerous factors.

References

Andersen LL, Andersen SP, Magnusson SP, Suetta C, Madsen JL, Christensen JR and Aagaard P. Changes in human muscle force-velocity relationship in response to resistance training and subsequent detraining. J.Appl. Physiol. 99:87-94. 2005. Hakkinen K, Allen M, Komi PV. Changes in isometric force-and relaxation time, electromyographic and muscle fibre characteristics of human skeletal muscle during strength training and detraining. Acta Physiol, Scand, 125:573-585. 1985. Hakkinen K, Komi PV. Electromyographic changes during strength training and detraining. Med Sci. Sport Exerc, 15:455-460. 1983. Hakkinen K, Komi PV, Allen M. Effect of explosive type strength training on isometric force and relaxation time, electromyographic and muscle fibre characteristics of leg extensor muscles. Acta Physiol. Scand. 125: 587-600. 1985. Izquierdo M, Ibanez J, Gonzlez-Badillo J, Ratamess NA, Kraemer WJ, Hakkinen K, Bonnabau H, Granados C, French D, and Gorostiaga EM. Detraining and tapering effects on hormonal responses and strength performance. Journal of strength and Conditioning Research, 2007m 21 (3), 768-775. Kraemer WJ, Koziris LP, Ratamess NA, Hakkinen K Triplett-Mcbride N, Fry AC, Gordon SE, Volek JS, French DN, Rubin MR, Gomez AL, Sharman MJ, Lynch JM, Izquierdo M, Newton RU, Fleck SJ. Detraining produces minimal changes in physical performance and hormonal variables in recreationally strength-trained men. J. Strength Cond. Res 16:373-382. 2002.

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