Research: Strength Training

This morning's inbox item: Strength and Conditioning Practices in Rowing. Researchers presented coaches in Great Britain with a questionnaire to help characterize and quantify the type of strength and conditioning used by their charges. Some of the more notable findings include:

• Almost all coaches (94%) reported their rowers performed strength training, with 81% using Olympic lifting
• The clean (63%) and squat (27%) were rated the most important prescribed exercises.
• Ninety-four percent indicated they conducted physical testing on their rowers, typically assessing cardiovascular endurance (80%), muscular power (70%), muscular strength (70%), and anaerobic capacity (57%).

It's What Everyone Does
Clearly strength training is important to high-level British rowing coaches. This seems consistent with many national team publications (e.g., Australia) and the governing body of international rowing (source) as well as articles in various rowing books (example) and magazines (example).

But why is strength training important?
The above study did not appear to ask why the coaches employed strength training, but maybe that question should be asked. A logical answer might be that strength training confers performance benefits as demonstrated in various studies. In fact, researchers have attempted to ascertain the benefits of strength training in rowing and these studies have generally shown few, if any, performance benefits. In one study (#4 below), strength training seemed to set back members of the US National Team.

What?! Blasphemy! This can't be right. Show me.

No Performance Benefits: Study 1
In The effect of velocity-specific strength training on peak torque and anaerobic rowing power. , Bell, G. J., Petersen, S. R., Quinney, A. H., & Wenger, H. A. divided 18 varsity oarsmen from the University of Victoria into three training groups, two of which performed circuit training (three circuits of 12 stations) four times a week for 5 weeks. One group performed the strength training at high velocity, while the other group performed them at slower velocity. A third group was a no-training control.

The results of this study are a bit surprising. Both training groups significantly increased their peak torque in knee extension--a primary rowing motion, with the high velocity group excelling at higher velocity and the lower velocity group excelling at lower velocity motions. Furthermore, researchers found high positive correlations between peak torque and anaerobic power outputs. So far, it sounds good for the effectiveness of this training regimen. However,  the improved peak torque did not translate into any performance benefits as tested on the rowing ergometer, leading the researchers to conclude:

These results indicate that velocity-specific strength training does not necessarily improve anaerobic power output in a different exercise mode despite the high positive correlation between isokinetic strength and anaerobic power output.

If your eyes started to glaze over with the terminology above, read this brief synopsis of the above study, a quote from which below (bold highlights are mine):

This finding was surprising because the strength program was specifically designed to enhance the strength of the muscle groups involved in rowing. Since power is dependent on both force and velocity, the observed improvements in torque with resistance training should, theoretically, have contributed to an increase in rowing power. That theoretical position was not supported by the results of this study in these high-caliber athletes. The lack of improvement contradicts the recommendations of many coaches and the content emphases of many rowing training programs.

Another reviewer concluded:

training effects were specific to the resistance training mode and did not transfer to the more complex action of rowing. Resistance training programs may actually restrict the volume of beneficial, sports specific training that can be achieved because of increased levels of fatigue.

Many reviewers have focused on this study because it is one of the few that existed up until recently.

No Performance Benefits: Study 2
More recently, in The effects of concurrent endurance and resistance training on 2,000-m rowing ergometer times in collegiate male rowers., Gallagher D, DiPietro L, Visek AJ, Bancheri JM, Miller TA "evaluated if high rep, low rep, or no weight training at all would be best suited for decreasing 2,000-m rowing ergometer times in male varsity rowers." 18 rowers were randomly assigned to the corresponding groups of control (CON), high-load low repetitions (HLLR), and low-load high repetitions (LLHR). Each group performed their regular varsity workouts and the two study groups performed their additional workouts. All groups were tested on the rowing ergometer before and after and all groups (including the control) improved their times. However, there was no statistical difference between the three groups. Oddly, the researchers concluded:

Overall, the current study demonstrates that although weight training does not create a statistically significant short-term training effect on rowing performance, the profound decreases in 2,000-m times seen in this study may be of practical significance for the oarsman.

Huh!? This seems like a rather odd conclusion given the data and statistical analysis. It would be comparable to saying that even though a pill did not exceed random chance in curing some disease, you should take it anyway.

One wonders if there had been a fourth group, one that performed the equivalent amount of work of the two study groups, but only rowing, what might have been the outcome.


Some Performance Benefits: Study 3
The research below is intriguing because it is the first study in my experience to show strength training may have some actual benefit to rowing performance. Unfortunately, the data don't seem to match the conclusions.

In Concurrent endurance and strength training not to failure optimizes performance gains., Izquierdo-Gabarren et al, took 43-trained male rowers and divided them into 4 groups, all of which continued with their normal endurance training, but one group performed four exercises to repetition failure(4RF), one group performed four exercises not to failure(4NRF), one group performed two exercises not to failure (2NRF) and one control group performed no additional training.

Various strength and rowing performance measurements were taken before and after 8 weeks of  training, including: "20-min all-out row test (W20min), average row power output eliciting a blood lactate concentration of 4 mmol.L (W4mmol.l), and power output in 10 maximal strokes (W10strokes)."

When the group participants hopped on the rowing ergometer, the researchers found no significant difference between all groups (including the control group) regarding performance at power eliciting a blood lactate concentration of 4 mmol.L. (this is a metric associated with anaerobic threshold or AT). This is somewhat surprising given that this is a fairly high intensity effort; one might have thought that the strength training groups might outperform the control group by some significant amount.

Interestingly, both the not-to-failure groups improved performance in the W20min test and the W10strokes tests, However, the group that only performed two exercises improved more than the group that performed four. "4NRF and 2NRF groups experienced larger gains in W10strokes (3.6% and 5%), and in W20min (7.6% and 9%)" compared with those found after 4RF (5.2% and 5.1 %)."

Notice the group that trained to failure (4RF) actually improved more than the other groups in power output in 10 maximal strokes.

One might reasonably conclude based on this limited information that the optimum training is two exercises not to failure (2NRF) because:

• this group improved 20-min all-out row test by 9% (more than any other group), and 
• this group was better than the 4NRF group in power output in 10 maximal strokes. 

However, the researchers arrived mysteriously at a different conclusion:

"An 8-wk linear periodized concurrent strength and endurance training program using a moderate number of repetitions not to failure (4NRF group) provides a favourable environment for achieving greater enhancements in strength, muscle power and rowing performance when compared with higher training volumes of repetitions to failure in experienced highly- trained rowers."

This is a baffling conclusion based on the data.

Finally, one might again have wanted an additional control group that performs the equivalent amount of work of the other non-control groups. It is possible, after all, that any performance differences (such as they are) were actually due to more training, not the particular type of training.

By the way, the full paper is available for your perusal.

No Performance Benefits: Study 4
In A Comparison of Traditional and Non-Traditional Off-Season Training Programs of Elite Rowers. Murray, T.; Grant, S.; Hagerman, F. FACSM; Staron, R.; Verdun, M.; Weinik, M., divided 30 elite (US Team members) rowers (men and women) into two groups, one that performed traditional off-season weight training (the lifting group) and one that did not (the no lifting group). Unlike the studies above, this study had the no-lifting group replace weight training with rowing ergometer work, tank or actual water rowing. The approximate duration of the different study conditions was 16 weeks.

The initial physiological evaluation was performed in December and repeated in April. Tests included a variety of heinous invasive measurements, including capillary lactate measurements and muscle biopsies. Other indignities included maximal squat and bench pulls, periodic 2500 meter and 10,000 meter ergometer tests. These athletes were poked, prodded and pricked.

Actual rowing performances were observed multiple times, culminating with the summer competitive rowing season. This was a real test on real rowers, with--as it turns out--real consequences.

The results are surprising even if you read some of the above studies. There was no significant differences between the two groups for such measurements as:

• max power output
• heart rate
• squat and bench pull strength
• stroke rating
• mechanical efficiency

However, in the rowing ergometer performance, the  no-lift group "achieved significantly faster competitive performance times than their L[ifting] counterparts at 2500 and 10000m"

Moreover, the no-lift group also statistically improved their absolute and relative VO2 during the 2000m test, while the lifting group did not.

The research summary is a sober indictment of traditional off-season strength training:

In summary, the results of this study appear to confirm data reported by our group in 1983, when it was evident that rowers who performed off-season weight training significantly reduced their aerobic capacities and as a result it was necessary for these athletes to work extremely hard to increase oxygen consumption to competitive levels.

Our data show that not only does supplemental weight training fail to improve physiological and competitive performance, but more importantly it appears that off-season weight training at 20-40% of total training time may actually detract from these performances...

Our data support our original hypothesis that elite rowers would probably benefit more from performing some type of rowing (either ergometer, tank or actual rowing) during the off-season than sharing training time with resistance training... subsequent competitive performances significantly favored the non-lifting groups.

That's It?
Strength training is a multi-billion dollar industry. Strength training is clearly widely advocated for and widely employed by rowers. You would think there would be more published studies regarding strength training and rowing performance. You'd think there'd be some studies that clearly show a performance benefit. It's possible that I've missed these studies, and if so, I'd be glad to summarize the findings on this site.