The S&C Research review service comes out on the first day of every month. Here is a preview of the February 2016 edition, which comes out next Monday. Each edition covers a wide range of exciting new research but this edition has a special theme of the leg press!
Why talk about the leg press?
The leg press attracts a certain amount of controversy. Some strength coaches regard it as a very useful tool, while others consider it totally useless. Among those coaches who regard it as a useful tool, most would be confident saying that it can develop muscular size, but often stop short of claiming that it can increase functional lower-body strength and power.
In reality, there has always been a fairly decent body of research showing that the leg press is useful for increasing functional strength in diseased populations when working in rehabilitation settings (Karlsen & Helgerud, 2009; and Wang et al. 2010). In such cases, long-term programs of leg press training improve walking efficiency, walking economy, and treadmill walking test time-to-exhaustion performance. Similarly, the leg press improves functional strength in the elderly (Correa et al. 2012; Ramírez-Campillo et al. 2014; and Pamukoff et al. 2014), including balance recovery, vertical jump height, number of bodyweight squats in 30 seconds, and short-distance sprint running ability. And leg press training even improves functional performance in young, untrained subjects, as Wawrzyniak et al. (1996) found that performance on a maximal single-leg hop for distance test was increased.
Does leg press training improve balance and jump height in amateur athletes?
The study: Effect of combined sensorimotor-resistance training on strength, balance, and jumping performance of soccer players, by Manolopoulos, Gissis, Galazoulas, Manolopoulos, Patikas, Gollhofer, and Kotzamanidis, in The Journal of Strength & Conditioning Research (2015)
What did the researchers do?
The researchers compared the effects of leg press alone with leg press resistance training in combination with sensorimotor (balance) training on:
- Balance (measured by the ability to maintain a stable one-leg stance posture on a force plate)
- Strength (as measured by 1RM leg press and maximum voluntary isometric contraction [MVIC] force)
- Rate of force development (RFD) (as measured in an isometric leg press set-up)
- Vertical jump height (as measured by squat jump performed on a force plate)
They studied these effects in a group of 20 amateur soccer players, randomly allocated into either a combined group or a resistance training only group. All subjects trained 2 times per week for 6 weeks. Both groups performed 5 sets of 8 repetitions to muscular failure on the leg press exercise, while the combined group also performed balance training involving 4 exercises for 5 sets of 30 seconds, with 30 seconds of rest between sets. The balance training was initially performed using a balance board and later with a soccer ball.
The researchers found that the movement of the center of pressure (COP) in both the anterior-posterior and medio-lateral axes decreased in both groups after training, but there was no difference in the size of the change between the groups. Similarly, vertical jump height increased in both groups, but the increase was similar in both groups. The researchers found that the leg press 1RM, MVIC force, and RFD measured at all time points increased in both groups, but there were no differences between the two groups. Therefore, the leg press resistance training program improved balance and vertical jump height in amateur soccer players (as well as 1RM leg press, MVIC force, and RFD). But adding another balance training intervention did not improve these effects.
Does leg press training improve measures of pain and also affect patellar realignment?
The study: Effect of leg press training on patellar realignment in patients with patellofemoral pain, by Peng & Song, in Journal of Physical Therapy Science (2015)
What did the researchers do?
The researchers compared the long-term effects of either leg press training and leg press with hip adduction training on:
- Patellar alignment (patella medio-lateral tilt angle and medio-lateral patellar displacement)
- Pain (measured with the visual analog scale [VAS] for pain).
The subjects were 17 patients with patellofemoral pain lasting >1 month, with the onset of pain being unrelated to trauma, randomly allocated into either a leg press group or a leg press with hip adduction group. All of the subjects performed a program of resistance training using the unilateral leg press exercise 3 times per week for 8 weeks, with 60% of 1RM for 5 sets of 10 reps. The leg press group used the leg press exercise, while the leg press with hip adduction group performed the leg press exercise while also carrying out simultaneous isometric hip adduction against an elastic resistance band.
The researchers found that neither of the patellar alignment measurements were altered by either of the leg press interventions. This indicates that neither leg press training program affected the alignment of the patellar in individuals with patellofemoral pain. Despite the lack of change in either measurement of patellar alignment, there was an improvement in pain scores in both groups, implying that they were equally effective. Since there was no control group that performed no exercise training, it is unclear whether this reduction in pain occurred as a result of the exercise training or purely through the natural course of the condition. Even so, since the beneficial effects on pain occurred in the absence of any changes in patellar alignment, this suggests that patellar malalignment may not be a key contributor to the problem of patellofemoral pain.
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