Variations in Verbal Encouragement Modify Isokinetic Performance.

Rendos, NK, Harriell, K, Qazi, S, Regis, RC, Alipio, TC, and Signorile, JF. Variations in verbal encouragement modify isokinetic performance. J Strength Cond Res 33(3): 708-716, 2019-Verbal instruction and encouragement are common in exercise testing; however, the verbiage used during exercise testing is rarely controlled despite the likelihood it may affect the participant's performance. Although variations in verbal cuing based on rate and intensity have been examined during isometric contractions, they have not been examined during isokinetic testing, which is a standardized assessment of muscle performance in athletic, rehabilitation, and research settings. This study examined the effects of 4 variations in verbal encouragement during isokinetic knee flexion and extension exercises. Twenty-three healthy participants (aged 19-34 years) completed 4 isokinetic testing sessions on a Biodex isokinetic dynamometer. Each session consisted of 5, 10, and 15 repetitions at 1.05 rad·s (60°·s), 3.14 rad·s (180°·s), and 5.24 rad·s (300°·s), respectively, separated by 5-minute passive recoveries. The variations in verbal encouragement randomized during each testing session used the following statements: (a) "as fast as you can" (FAST); (b) "as hard as you can" (HARD); (c) "as hard and as fast as you can" (BOTH); and (d) no verbal encouragement (NO CUE). Repeated-measures analyses of variance with a Bonferroni post hoc analysis revealed that the FAST and BOTH verbal cues produced greater work, peak torque, and power at all 3 speeds of isokinetic testing. These findings indicate the verbal cues "as fast as you can" and "as hard and as fast as you can" should be used to maximize performance during isokinetic testing.

Differences in Muscle Activation and Kinematics Between Cable-Based and Selectorized Weight Training.

Signorile, JF, Rendos, NK, Heredia Vargas, HH, Alipio, TC, Regis, RC, Eltoukhy, MM, Nargund, RS, and Romero, MA. Differences in muscle activation and kinematics between cable-based and selectorized weight training. J Strength Cond Res 31(2): 313-322, 2017-Cable resistance training machines are showing resurgent popularity and allow greater number of degrees of freedom than typical selectorized equipment. Given that specific kinetic chains are used during distinct activities of daily living (ADL), cable machines may provide more effective interventions for some ADL, whereas others may be best addressed using selectorized equipment. This study examined differences in activity levels (root mean square of the EMG [rmsEMG]) of 6 major muscles (pectoralis major, PM; anterior deltoid, AD; biceps brachii, BB; rectus abdominis, RA; external obliques, EO; and triceps brachii, TB) and kinematics of multiple joints between a cable and standard selectorized machines during the biceps curl, the chest press, and the overhead press performed at 1.5 seconds per contractile stage. Fifteen individuals (9 men, 6 women; mean age ± SD, 24.33 ± 4.88 years) participated. Machine order was randomized. Significant differences favoring cable training were seen for PM and AD during biceps curl; BB, AD, and EO for chest press; and BB and EO during overhead press (p ≤ 0.05). Greater starting and ending angles were seen for the elbow and shoulder joints during selectorized biceps curl, whereas hip and knee starting and ending angles were greater for cable machine during chest and overhead presses (p < 0.0001). Greater range of motion (ROM) favoring the cable machine was also evident (p < 0.0001). These results indicate that utilization patterns of selected muscles, joint angles, and ROMs can be varied because of machine application even when similar exercises are used, and therefore, these machines can be used selectively in training programs requiring specific motor or biomechanical patterns.

Differences in Muscle Activity During Cable Resistance Training Are Influenced by Variations in Handle Types.

Rendos, NK, Heredia Vargas, HM, Alipio, TC, Regis, RC, Romero, MA, and Signorile, JF. Differences in muscle activity during cable resistance training are influenced by variations in handle types. J Strength Cond Res 30(7): 2001-2009, 2016-There has been a recent resurgence in the use of cable machines for resistance training allowing movements that more effectively simulate daily activities and sports-specific movements. By necessity, these devices require a machine/human interface through some type of handle. Considerable data from material handling, industrial engineering, and exercise training studies indicate that handle qualities, especially size and shape, can significantly influence force production and muscular activity, particularly of the forearm muscles, which affect the critical link in activities that require object manipulation. The purpose for this study was to examine the influence of three different handle conditions: standard handle (StandH), ball handle with the cable between the index and middle fingers (BallIM), and ball handle with the cable between the middle and ring fingers (BallMR), on activity levels (rmsEMG) of the triceps brachii lateral and long heads (TriHLat, TriHLong), brachioradialis (BR), flexor carpi radialis (FCR), extensor carpi ulnaris, and extensor digitorum (ED) during eight repetitions of standing triceps pushdown performed from 90° to 0° elbow flexion at 1.5 s per contractile stage. Handle order was randomized. No significant differences were seen for triceps or BR rmsEMG across handle conditions; however, relative patterns of activation did vary for the forearm muscles by handle condition, with more coordinated activation levels for the FCR and ED during the ball handle conditions. In addition, the rmsEMG for the ED was significantly higher during the BallIM than any other condition and during the BallMR than the StandH. These results indicate that the use of ball handles with the cable passing between different fingers can vary the utilization patterns of selected forearm muscles and may therefore be advantageous for coaches, personal trainers, therapists, or bodybuilders for targeted training or rehabilitation of these muscles.