Summary. Cancer rehabilitation programs mainly involve endurance training while little attention has been paid to strength training. Breast cancer (BC) patients lose muscle strength while undergoing adjuvant treatment, thus affecting daily activities and quality of life. Maximal strength training, with an emphasis on velocity in the concentric phase, improves maximal strength and muscle force development characteristics. However, the effect of maximal strength training on quality of life for BC patients undergoing treatment remains elusive. Consequently, the aim of this study was to evaluate the effectiveness of maximal strength training in Health related quality of life in women with newly diagnosed BC. Materials and Methods: 55 BC patients with disease stage I–III were randomized into a training group and control group. The training group performed maximal strength training twice a week for 3 months, whereas the control group followed prescribed treatment without strength training. Overall quality of life was measured by The European Organization for Research and Treatment of Cancer Core Quality of life Questionnaire-C30 and additional BC module BR23 before and after the intervention. Results: The results obtained from pre-tests and those obtained after 3 months of intervention revealed that patients in the training group significantly increased one repetition maximum, by 20.4 kg (20%) (p = 0.001, d = 0.9). Simultaneously, statistically significant alterations were observed in this variable for the control group, one repetition maximum decreased by 8.9 kg (9%) (p = 0.001, d = 0.5). The overall quality of life improved significantly by 13% for the training group with large effect (p = 0.002, d = 0.6), but no relevant changes were observed in the control group (p = 0.44, d = 0.2). Results revealed remarkable changes in overall quality of life after 3-month post-test period between the two groups with large effect (p = 0.002, d = 0.9). The training sessions had helped in diminishing the sense of fatigue by 24% (p = 0.03, d = 0.6), while it had got worse by 25% (p = 0.02, d = 0.4) for the control group. Again, the data on large effect were noticed to differ between the groups (p = 0.01, d = 0.6). Conclusion: Maximal strength training for BC patients was well tolerated, safe and feasible and showed strength improvements that led to improved muscle strength and improved overall quality of life. These data certainly support the therapeutic role for maximal strength training in the treatment of BC.

Background and Purpose Adjuvant breast cancer therapy may reduce maximal muscle strength, muscle mass, and functional performance. Although maximal strength training (MST) has the potential to counteract this debilitating outcome and is shown to be superior to low- and moderate-intensity strength training, it is unknown if it can elicit effective adaptations in patients suffering treatment-induced adverse side effects. Methods Fifty-five newly diagnosed stage I to III breast cancer patients (49 ± 7 yr) scheduled for adjuvant therapy were randomized to MST or a control group. The MST group performed 4 × 4 repetitions of dynamic leg press at approximately 90% of one-repetition maximum (1RM) twice a week for 12 wk. Results In the MST group, improvements in 1RM (20% ± 8%; P < 0.001) were accompanied by improved walking economy (9% ± 8%) and increased time to exhaustion during incremental walking (9% ± 8%; both P < 0.01). Moreover, the MST group increased 6-min walking distance (6MWD; 10% ± 7%), and chair rising (30% ± 20%) and stair climbing performance (12% ± 7%; all P < 0.001). All MST-induced improvements were different from the control group (P < 0.01) which reduced their 1RM (9% ± 5%), walking economy (4% ± 4%), time to exhaustion (10% ± 8%), 6MWD (5% ± 5%), chair rising performance (12% ± 12%), and stair climbing performance (6% ± 8%; all P < 0.01). Finally, although MST maintained estimated quadriceps femoris muscle mass, a decrease was observed in the control group (7% ± 10%; P < 0.001). The change in 1RM correlated with the change in walking economy (r = 0.754), time to exhaustion (r = 0.793), 6MWD (r = 0.807), chair rising performance (r = 0.808), and stair climbing performance (r = 0.754; all P < 0.001). Conclusions Lower-extremity MST effectively increases lower-extremity maximal muscle strength in breast cancer patients undergoing adjuvant therapy and results in improved work economy, functional performance, and maintenance of muscle mass. These results advocate that MST should be considered in breast cancer treatment.

Background: Breast cancer (BC) patients lose muscle strength during adjuvant treatment, thus affecting physical functioning. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength and walking efficiency. However, the effect of MST for BC patients undergoing treatment remains elusive. Aim: The aim of this study was to examine the feasibility and effects of such training in BC patients during clinical treatment on maximal muscle strength and functional performance. Methods: Thirty patients (46 ± 9 yr) with stage I-III BC were randomized to training group (TG) or control group (CG). TG performed MST twice a week for 3 months and CG followed prescribed BC treatment without strength training. TG performed four sets of four repetitions (4×4) of dynamic leg press with an emphasis on the maximal mobilization of force in the concentric action and with a progressively adjusted intensity corresponding to 85%–90% of one repetition maximum (1RM). Results: After the MST period, TG displayed significant 25 ± 7 kg (23%) increase in leg press 1RM ( P = 0.001). The strength improvements led to a significant increase in 6 minute walk distance (8%), 30-second chair test (23%), stair climb test (17%), and to a significant increase in walking performance of (8%) measured on an incremental treadmill test to exhaustion. In 3 months' posttest CG displayed significant 10 ± 8 kg (9%) decrease in 1RM ( P = 0.006). Reduced muscle strength leg to a significant decrease in 6 minute walk distance (6%), 30-second chair test (14%), stair climb test by (8%), and walking performance reduced significantly by (17%). Significant changes from pre to 3 months' posttest were observed between TG and CG in all functional performance measured variables. Conclusion: Maximal strength training was feasible during treatment and increased maximal muscle strength in BC patients. Increased strength led to improved functional performance after 24 training sessions each lasting only 20 min. Our results suggest that application of MST could accompany clinical training as a part of the treatment of BC patients. This training form showed excellent improvements in physical function tests and, thus should be implemented as a part of the breast cancer rehabilitation programs.

Objective. Breast cancer (BC) is the most frequently diagnosed type of cancer among women, with more than 2 million new cases and over 600 000 deaths annually (Bray et al., 2018), and its global incidence is steadily rising. BC patients through the cancer continuum experience complex health and psychosocial challenges. BC and anti-cancer treatment accompanied by an inactive lifestyle may further impair muscle strength and muscle force development characteristics. Historically, patients diagnosed with cancer were advises to rest and avoid vigorous activity following their diagnosis, but this dogma has changed markedly over the last 20 years as exercise oncology intervention studies have gained broad acceptance and acknowledgment. Strength training can optimally affect muscles and increased muscle strength may contribute to participation in daily activities, thus potentially improving the health-related quality of life (HRQoL). However, the optimal type, intensity and frequency of strength training, as a part of cancer care, that will most enhance muscle strength during anti-cancer treatment is yet unknown. Christensen et al. (Christensen et al., 2014) investigated newly confirmed (breast, gastric, colorectal, lung and pancreas) cancer patients and concluded that these patients had 0.9 kg lower muscle mass compared with healthy controls even before the initiation of anti-cancer treatment. Furthermore, during adjuvant chemotherapy, BC patients lost 1.3 kg lean body mass (LBM), and continued to lose LBM after therapy was completed. Ultimately, BC survivors evaluated after completion of primary therapy displayed 20–30% lower muscle strength compared with healthy counterparts. Most physical activity interventions for BC patients combine aerobic endurance training with strength training and diverse relaxation therapies, hence making it more complicated to evaluate the impact of training type. There has been a limited number of well-defined clinical trials on BC patients that include higher intensity strength training, moreover when intervention is administered during adjuvant treatment. Training intensities vary substantially across cancer studies ranging from 25–80% of one-repetition maximum (1RM), although, it has been documented that higher training intensities yield greater strength gains in young healthy individuals (Campos et al., 2002). Similarly, greater gains in muscle strength are documented with increasing intensity for cancer patients, however, these patients are likely to have some improvement even at low training intensities (Fairman et al., 2017). The common consent from clinical trials when strength training interventions were applied for cancer patients states that training programs were well tolerated, they are safe, feasible and showed strength improvements that led to improved physical functioning and improved HRQoL (Segal et al., 2003), (De Backer et al., 2007), (Battaglini et al., 2014). Recognizing that training intensity during strength training is a key factor to improve maximal muscular strength and strength related characteristics. Therefore, well-defined training methods with high intensity could also be preferable to induce greater physiological adaptations, thus contribute to faster recovery from specific cancer treatment and enhancing the completion of prescribed anti-cancer treatment.

Objective. Breast cancer (BC) is the most frequently diagnosed type of cancer among women, with more than 2 million new cases and over 600 000 deaths annually (Bray et al., 2018), and its global incidence is steadily rising. BC patients through the cancer continuum experience complex health and psychosocial challenges. BC and anti-cancer treatment accompanied by an inactive lifestyle may further impair muscle strength and muscle force development characteristics. Historically, patients diagnosed with cancer were advises to rest and avoid vigorous activity following their diagnosis, but this dogma has changed markedly over the last 20 years as exercise oncology intervention studies have gained broad acceptance and acknowledgment. Strength training can optimally affect muscles and increased muscle strength may contribute to participation in daily activities, thus potentially improving the health-related quality of life (HRQoL). However, the optimal type, intensity and frequency of strength training, as a part of cancer care, that will most enhance muscle strength during anti-cancer treatment is yet unknown. Christensen et al. (Christensen et al., 2014) investigated newly confirmed (breast, gastric, colorectal, lung and pancreas) cancer patients and concluded that these patients had 0.9 kg lower muscle mass compared with healthy controls even before the initiation of anti-cancer treatment. Furthermore, during adjuvant chemotherapy, BC patients lost 1.3 kg lean body mass (LBM), and continued to lose LBM after therapy was completed. Ultimately, BC survivors evaluated after completion of primary therapy displayed 20–30% lower muscle strength compared with healthy counterparts. Most physical activity interventions for BC patients combine aerobic endurance training with strength training and diverse relaxation therapies, hence making it more complicated to evaluate the impact of training type. There has been a limited number of well-defined clinical trials on BC patients that include higher intensity strength training, moreover when intervention is administered during adjuvant treatment. Training intensities vary substantially across cancer studies ranging from 25–80% of one-repetition maximum (1RM), although, it has been documented that higher training intensities yield greater strength gains in young healthy individuals (Campos et al., 2002). Similarly, greater gains in muscle strength are documented with increasing intensity for cancer patients, however, these patients are likely to have some improvement even at low training intensities (Fairman et al., 2017). The common consent from clinical trials when strength training interventions were applied for cancer patients states that training programs were well tolerated, they are safe, feasible and showed strength improvements that led to improved physical functioning and improved HRQoL (Segal et al., 2003), (De Backer et al., 2007), (Battaglini et al., 2014). Recognizing that training intensity during strength training is a key factor to improve maximal muscular strength and strength related characteristics. Therefore, well-defined training methods with high intensity could also be preferable to induce greater physiological adaptations, thus contribute to faster recovery from specific cancer treatment and enhancing the completion of prescribed anti-cancer treatment.