In a special new issue of NSCA Coach dedicated entirely to all things basketball (Olympics anyone?), the NSCA and the National Basketball Strength and Conditioning Association (NBSCA) collaborated to publish the latest in basketball science and research. While every article in this issue is worth reading, especially if you are a basketball coach or strength coach, we wanted to highlight one written by a strength coach for the Sacramento Kings, Ramsey Nijem, entitled "Single-Leg and Double-Leg Training Implications for Basketball."
A bit of background: there is debate in the S&C community about the right or best way to prepare basketball athletes (and all athletes in general) for the demands of the sport. Basketball players need to be able to run, cut, change direction, and jump (on one leg and two) in order to be successful—so which is the best choice for exercise selection in a strength and conditioning program: unilateral (single-leg) or bilateral (double-leg) movements?
Bilateral vs. Unilateral Training
The argument for emphasizing bilateral training for basketball athletes centers on the fact that it offers potential for generating greater absolute force and velocity. After all, you can back squat more absolute weight than you can squat on one leg! Unilateral training, on the other hand, is considered by others to be superior due to the bilateral force deficit (BLFD), in which the sum of the force generated by each single leg is actually greater than the force generated by both legs at once. In other words, the sum of your 1RMs in a Bulgarian Split Squat (rear-foot elevated squat, so a single-leg movement) on your right and left legs will actually be MORE than your Back Squat 1RM. Crazy phenomenon, huh?
In his article, Nijem first reviews the available literature on bilateral vs. unilateral training, then draws some practical conclusions for what the data means for basketball players from a strength training perspective. He reviews several different studies that examined the effect of bilateral vs. unilateral training on endurance, strength and power, and sprint ability and agility.
One study looked at the effects of double-leg and single-leg training on leg strength and fatigue. Right in line with the principle of specificity (a foundational principle of strength and conditioning science which states that, if you want to improve a specific training adaptation, you must target it with specific exercises—that which is specifically targeted will be improved, like a biceps curl improving biceps strength), the study found that single-leg training improved single-leg strength and decreased single-leg fatigue, with similar results in double-leg training. So, when it comes to endurance, gains appear to be specific to the type of training—highlighting the importance of both types of training in a comprehensive sport performance training program.
Strength and Power
Several recent studies on neuromuscular adaptations in single- vs. double-leg exercises found that unilateral and bilateral training can increase BOTH unilateral and bilateral strength and power. However, the magnitude of strength and power increases were GREATER in single-leg exercises, indicating that, while strength and power improvements are not exclusive to training type, the magnitude of improvement depends on the type of training performed. I.e., while single-leg power is improved by double-leg training, it is BEST improved through single-leg training. This suggests the importance of specificity as it applies to exercise selection for sports, in order to ensure the best adaptations are attained from training protocols.
Sprint Ability and Agility
In what Nijem calls "the most practical study comparing unilateral and bilateral training to date," researchers compared the effects of single-leg and double-leg exercises on strength, agility, and sprint performance. Subjects were tested in the Rear-Foot Elevated Split Squat (Bulgarian Split Squat), Back Squat, pro-agility test, and 10-m and 40-m sprints, and results showed equal improvements between the unilateral and bilateral training groups. This is compelling evidence for the effectiveness of both single- and double-leg exercises on improving strength, sprint, and change of direction speed for basketball players.
And yet, while all the studies provide some insight into the effects of single-leg and double-leg training, most were conducted over fairly short time periods (8 weeks or less). One study in particular performed a longer-term study, which looked at the effects of each type of training on performance pre-training, mid-training (after 6 weeks), post-training (after 12 weeks), and after a 4-week detraining period (from weeks 12 to 16). Since this 16-week period mimics a more practical off-season training calendar for basketball players, the results of this study are perhaps the most applicable to Volt athletes.
The research found that unilateral training improved in all performance aspects by 6 weeks—but showed NO further improvements from 6-12 weeks, and has substantial DECREASES in performance by 16 weeks. In contrast, the bilateral training group improved in only 2 of the 4 performance tests, but improvements continued through week 12 and DID NOT decrease in weeks 12-16. So, what do these results mean for basketball athletes?
Nijem concludes that the literature shows compelling evidence for the practicality of BOTH types of training for improving endurance, strength, power, sprint speed, and agility (change of direction performance)—but that the time-dependent results of single-leg vs. double-leg training must be taken into account when designing an effective basketball training program.
"...unilateral training appears to elicit rapid adaptations while bilateral training may take a bit longer to improve performance but the adaptations appear more resistant to detraining regression."
This is exactly why Volt Basketball programs include both types of training throughout the course of the off-season training calendar, and emphasize single-leg plyometric training closer to the start of the season. This allows athletes to improve all performance markers throughout the off-season, and develop more basketball-specific single-leg power at just the right time to help them peak for the start of the season. This is why Volt basketball athletes will see more single-leg jumps (like Explosive Step-ups, Ice Skaters, and Single-Leg Box Jumps) in the last few blocks leading up to their season start date: to help maximize the transfer of sport-specific performance to the court.
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Learn more about Christye and read her other posts | @CoachChristye