Comparison of two resistance training protocols, 6RM versus 12RM, to increase the 1RM in healthy young adults. A single-blind, randomized controlled trial.

PURPOSE: The purpose of the study is to compare the effect in healthy young adults of two resistance training protocols, six-repetition maximum (RM) versus 12RM on maximum strength (1RM). METHOD: A single-blind, randomized controlled trial was used in the study. Sixty-two healthy physical therapy students, with age (mean [+standard deviation]) 23 (+2.6) years, weight 67.4 (+11.7) kg and height 171.7 (+8.4) cm, of both genders who were recreationally active, but not training systematically, volunteered to participate in the study. They were randomized into two groups (group 1: 24 women and 8 men; group 2: 23 women and 7 men) by a block randomization procedure that ensured equal gender distribution. Sealed envelopes were used to conceal allocation to groups. INTERVENTIONS: Group 1 did three sets of 6RM of each exercise, and group 2 did three sets of 12RM. Both groups performed the exercises twice per week for 8 weeks with 3 minutes rest between sets and exercises. Primary outcomes were maximum strength defined as one-repetition maximum squat (1RMSq) for lower-body strength and bench press (1RMBp) for upper-body strength. Secondary outcomes were body weight and Uro Kaleva Kekkonen (UKK) Fitness Index. RESULTS: Both groups increased strength significantly (p < 0.001) in 1RMSq (6RM 13.6%, 12RM 13.5%) and 1RMBp (6RM 9.2%, 12RM 8.4%). There was no significant difference in the change between the two groups, no change in body weight and only a small increase in UKK Fitness Index. CONCLUSION: Both 6RM and 12RM training protocols improve maximum strength in recreationally active healthy young adults, with no significant difference between the protocols.

Effects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy.

BACKGROUND: Eccentric exercises (EEs) are recommended for the treatment of Achilles tendinopathy, but the clinical effect from EE has a slow onset. HYPOTHESIS: The addition of low-level laser therapy (LLLT) to EE may cause more rapid clinical improvement. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 52 recreational athletes with chronic Achilles tendinopathy symptoms were randomized to groups receiving either EE + LLLT or EE + placebo LLLT over 8 weeks in a blinded manner. Low-level laser therapy (lambda = 820 nm) was administered in 12 sessions by irradiating 6 points along the Achilles tendon with a power density of 60 mW/cm(2) and a total dose of 5.4 J per session. RESULTS: The results of the intention-to-treat analysis for the primary outcome, pain intensity during physical activity on the 100-mm visual analog scale, were significantly lower in the LLLT group than in the placebo LLLT group, with 53.6 mm versus 71.5 mm (P = .0003) at 4 weeks, 37.3 mm versus 62.8 mm (P = .0002) at 8 weeks, and 33.0 mm versus 53.0 mm (P = .007) at 12 weeks after randomization. Secondary outcomes of morning stiffness, active dorsiflexion, palpation tenderness, and crepitation showed the same pattern in favor of the LLLT group. CONCLUSION: Low-level laser therapy, with the parameters used in this study, accelerates clinical recovery from chronic Achilles tendinopathy when added to an EE regimen. For the LLLT group, the results at 4 weeks were similar to the placebo LLLT group results after 12 weeks.

Is mechanical pain threshold after transcutaneous electrical nerve stimulation (TENS) increased locally and unilaterally? A randomized placebo-controlled trial in healthy subjects.

BACKGROUND AND PURPOSE: It is not fully understood how transcutaneous electrical nerve stimulation (TENS) intensity affects mechanical pain threshold. METHOD: Sixty-six healthy volunteers (13 male, 53 female; 132 hands) without prior experience of TENS participated in the study, which comprised a randomized single-blind controlled trial. TENS was administered for 20 minutes through electrodes (25 x 25 mm) placed on the hands and forearms with a fixed frequency of 100 Hz and pulse duration of 150 micros. TENS intensity was randomized and allocated in a concealed manner so that one arm received TENS with stimulation intensity set at participants' subjective sensory threshold and the other received TENS with stimulation intensity continuously adjusted by physiotherapists to a strong but comfortable non-painful stimulation. Observers were blinded to stimulation intensity levels. RESULTS: Mechanical pain threshold increased significantly, by a mean total of 0.79 kg/cm2 (95% confidence interval [95% CI]: 0.54-1.04) (p < 0.001) on the strong but comfortable non-painful stimulation side. The mean change in mechanical pain threshold on the sensory threshold side was 0.19 kg/cm2 and did not reach statistical significance (95% CI-0.15 to 0.51). The mean stimulation intensity level for sensory threshold was 6.7 mA (95% CI: 5.65 to 7.83) which was significantly lower (p < 0.001) than the mean stimulation intensity for the strong stimulation, which was 20.5 mA (95% CI 16.6 to 24.4), respectively. The strong stimulation levels were, on average, 3.05 times higher than sensory threshold, but individual variations were large (range 1.2-6.1). CONCLUSIONS: TENS administered at a strong but comfortable non-painful stimulation intensity increases mechanical pain threshold ipsi-laterally in healthy subjects, whereas TENS administered at sensory threshold intensity does not. TENS may be ineffective if electrodes are placed contralaterally or distant to the pain site and if stimulation intensity levels are not titrated to subjective strong levels. Further clinical trials are needed to clarify if these findings may also be generalized to populations of chronic pain sufferers.