Core Muscle Activation During Unstable Bicep Curl Using a Water-Filled Instability Training Tube.

Glass, SC, Blanchette, TW, Karwan, LA, Pearson, SS, O'Neil, AP, and Karlik, DA. Core muscle activation during unstable bicep curl using a water-filled instability training tube. J Strength Cond Res 30(11): 3212-3219, 2016-The purpose of this study was to assess compensatory muscle activation created during a bicep curl using a water-filled, unstable lifting tube. Ten men (age = 21 ± 1.6 years, height = 180.0 ± 3.3 cm, mass = 87.4 ± 15.0 kg) and 10 women (age = 19.6 ± 1.3 years, height = 161.4 ± 12.0 cm, mass = 61.2 ± 7.4 kg) completed bicep curls using an 11.4-kg tube partially filled with water during a 50% open-valve, 100% open, and control setting. Subjects completed 8 repetitions within each condition with integrated electromyographic signal (converted to percent maximal voluntary contraction) of the bicep, deltoid, rectus abdominus, and paraspinal muscles measured. Compensatory activation was determined using the natural log of coefficient of variation across concentric (CON) and eccentric (ECC) contractions. There were no differences between gender for any condition. Significant variability was seen across treatments for paraspinal muscles for CON and ECC at 50% (CON LnCV = 3.13 ± 0.56%, ECC LnCV = 3.34 ± 0.58%) and 100% (CON = 3.24 ± 0.34%, ECC = 3.46 ± 0.35%) compared with control (CON = 2.59 ± 0.47%, ECC = 2.80 ± 0.61%). Deltoid variability was greater at the 100% open setting (CON = 3.51 ± 0.53%, ECC = 3.56 ± 0.36%) compared with control (CON = 2.98 ± 0.35%, ECC = 2.97 ± 0.45%). The abdominal CON 100% showed variability (3.02 ± 0.47%) compared with control (2.65 ± 0.43%). Bicep activation remained unvaried. Compensatory activation of postural muscles contribute to postural stability. This device may be a useful tool for neuromuscular training leading to improved stability and control.

The Effect of Foam Rolling Duration on Hamstring Range of Motion.

UNLABELLED: Musculoskeletal health benefits from flexibility training and maintaining a functional, or sport specific, range of motion is important to one's overall fitness. Commercial foam rollers are commonly used in gyms, therapy clinics and homes, yet data are lacking on the optimal rolling duration and effect on range of motion. PURPOSE: The purpose of this study was to examine the effect of varied durations of a commercial foam roller treatment on hamstring range of motion. METHODS: The knee extension range of motion of 33 college aged men and women (age= 20±1.5y, mass= 72.2±10.8 kg) was assessed after a short (2 sets of 10s) and long (4 sets of 30s) duration of hamstring self-administered myofascial release using a commercial foam roller. A one way ANOVA was performed to compare the mean knee extension angle for each condition to baseline measures. RESULTS: Results indicated that neither the short duration (67.30 ± 10.60 deg) nor long duration (67.41 ± 10.81 deg) rolling condition produced significant increases in knee extension compared to baseline (67.70 ± 9.90 deg). CONCLUSION: Self-administered foam rolling for a total duration of up to 2 minutes is not adequate to induce improvements in knee joint flexibility. Contributing factors may include the amount of pressure imparted by the commercial roller as well as duration of treatment.